MOTORS  AH 
MOTORING 


HENRY  J .  SPOONER 


CHESTKR  H.  HEUSER, 

THE  WISTAR  INSTITUTE 

PHILADELPHIA,  PA. 


MOTORS  AND  MOTORING 


Volumes  now  ready: 
BALLOONS,  AIRSHIPS,  AND  FLYING  MACHINES. 

By  GERTRUDE  BACON. 
MOTORS  AND  MOTORING.     By  Professor  HENKY  SPOONER, 

C.E.,  F.G.S. 

RADIUM.     By  DR.  HAMPSON. 

WIRELESS  TELEGRAPHY.     By  S.  G.  BUBBOW. 
And  Others  in  Preparation. 


MOTORS 

AND 

MOTORING 


BY 
HENRY  J.  SPQ/ONER,  C.E. 

M.INST.M.E.,  A.M.INST.C.E.. 
F.O.S. 


NEW  YORK 
DODD,  MEAD  &  COMPANY 

1908 


COPYHIGHT,     1905, 
BY 

DODD,  MEAD  &  COMPANY 


PREFACE 

WITH  the  object  of  assisting  beginners  to  acquire  use- 
ful information  relating  to  motors  and  motoring,  the 
author  consented  to  write  this  little  work,  much  of  the 
matter  consisting  of  what  may  be  considered  an  intro- 
duction to  the  mechanics  of  motoring.  He  has  endeav- 
ored to  explain  things  in  non-technical  language  as  far 
as  practicable,  and  in  such  a  way  that  those  who  have 
not  the  time,  inclination,  or  opportunity  to  study  any 
of  the  large  books  on  the  subject,  may  easily  be  able 
to  get  a  general  grasp  of  the  principles  which  underlie 
the  construction,  assembling,  and  working  of  gasolene 
cars. 

The  Gasolene  Engine  System  is  first  dealt  with,  and 
a  careful  examination  of  Fig.  1,  with  the  assistance  of 
the  accompanying  text,  should  enable  the  reader  to 
understand  the  relationship  and  interdependence  of  its 
various  parts;  these  parts  being  further  dealt  with  in 
separate  articles,  not  the  least  important  of  which  is 
No.  12,  on  the  Float-Feed  Carburettor,  which  is  ex- 
plained with  the  assistance  of  Fig.  6,  specially  devised 
to  show,  on  a  single  drawing,  the  important  features  of 
the  best-known  carburettors,  an  expedient  the  author 
has  found  very  useful  for  educational  purposes. 

Most  of  the  figures  are  diagrammatic,  and  have  been 
drawn  in  such  a  way  as  to  give  prominence  to  their  im- 
portant features,  whilst,  for  simplicity  sake,  minor  de- 
tails have  been  omitted;  the  leading  parts  being  shaped 
that  their  functions  can  be  best  understood  by  the 
novice,  and  these  remarks  particularly  apply  to  Figs. 
18  and  19. 

No  attempt  has  been  made  to  describe  any  particular 
car,  as  the  details  of  construction  of  any  one  make  nec- 
vii 


viii  PREFACE 

essarily  differ  in  many  respects  from  all  others.  But 
the  author  hopes  that  the  contents  of  the  following 
pages  will  help  the  novice  to  trace  out  easily  the  run  of 
the  various  connections,  pipes,  leads,  etc.,  on  a  given 
car,  and  to  understand  quickly  its  general  arrangement 
and  working,  and  also  become  acquainted  with  the 
methods  of  adjustment  and  lubrication  peculiar  to  it. 
All  this  can  be  much  facilitated  by  referring  to  the  In- 
struction Books  now  supplied  with  most  cars,  and  by 
reading  week  by  week  one  or  more  of  the  admirable 
technical  journals  which  so  loyally  and  ably  represent, 
promote,  and  encourage  the  pastime  and  industry. 
Although,  due  to  the  exigencies  of  space,  the  author 
has  had  to  confine  himself  mainly  to  motor  cars,  it 
should  not  be  overlooked  that  gasolene  motors,  whether 
they  be  used  to  propel  cars,  boats,  cycles,  or  machinery, 
have  much  in  common. 


ILLUSTRATIONS 

PAGE 

Fig.      1.   DlAGEAMATIC    SKETCH    OF   THE    COMPLETE    GASO- 
LENE MOTOR   SYSTEM, 5 

Figs.  2  to  5.  DIAGRAMMATIC  DRAWINGS   SHOWING  THE 

FOUR  STROKES  OF  THE  OTTO  CYCLE 9 

Fig.     6.  FLOAT-FEED    CARBURETTOR, 19 

Fig.    7.  THE   DE   DION    SURFACE   CARBURETTOR,    ...  25 
Figs.  8  to  10.  MIXING  CHAMBER  OR  TWIN  TAP  OF  DE  DION 

CARBURETTOR, 27 

Fig.  11.  SPARKING  PLUG 43 

Fig.  12.  NORMAL  INDICATOR  DIAGRAM — GOOD  IGNITION,  .  53 

Fig.  13.  INDICATOR  DIAGRAM — LATE  IGNITION,     ....  53 

Fig.  14.  INDICATOR  DIAGRAM — PRE-IGNITION, 53 

Fig   15.  INDICATOR  DIAGRAM — BACK-FIRING, 53 

Fig.  16.  COMMUTATOR,  OH  CURRENT  DISTRIBUTOR   (PAN- 

iiARD    TYPE), 55 

Fig.  17.  TYPICAL  MUFFLER, 62 

Fig.  18.  DRIVE-THROUGH    SIDE    CHAINS, 66 

Fig.  19.  LIVE  AXLE  OR  CARDAN  DRIVE, 68 

Fig.  20.  PANHARD  CLUTCH 72 


INTRODUCTION 

1.  No  one  can  fail  to  notice  the  growing  interest  the 
typical  "man  in  the  street"  is  taking  in  Motors1  and 
Motoring.  His  eyes  instinctively  turn  critically  to  view 
each  passing  car,  and  he  knows  that  a  peculiar  ticking 
noise  is  a  sure  indication  of  the  approach  of  an  electric 
carriage,  and  light  puffs  of  steam  from  underneath  a 
car2  a  certain  sign  that  it  is  a  steam  vehicle,  whilst  his 
ear  is  so  delicately  attuned  to  the  wide  range  of  detona- 
tions, due  to  the  working  of  gasolene  motors,  that  he  is 
rarely  at  fault  in  placing  such  cars  in  the  right  cate- 
gory; but  should  he  be  in  doubt,  the  offensive  odor3  of 
the  exhaust  gases  from  the  cars  too  often  give  his  olfac- 
tory organ  an  opportunity  of  assisting  in  the  matter, 
and  he  is  generally  able  to  differentiate  between  the 
various  types  of  cars  in  use.  Presumably  he  has  not 
failed  to  notice  that  the  electric  car  is  used  almost  ex- 
clusively for  town  work,  often  in  the  form  of  a 
brougham.  Its  great  weight  for  a  comparatively  small 
power,  the  limited  distance  it  can  run  without  recharg- 
ing the  batteries,  to  say  nothing  of  its  cost,  and  the  cost 
of  running,  precludes  this  otherwise  almost  perfect  car 
from  use  for  touring  purposes,  so  that  for  long  dis- 

1  Motor  is  a  recognized  abbreviation  of  "  Motor  Car " ; 
strictly  speaking,  the  motor  is  the  engine,  whilst  a  motor 
car,  autocar,  or  automobile,  as  it  is  sometimes  called,  is  the 
name  for  both  carriage  and  motor. 

2  It  should  be  mentioned  that  some  of  the  best  makes 
seldom,  if  ever,  show  any  exhaust. 

3  The  obnoxious  odor  of  the  exhaust  gases  that  so  often 
offend,  is  largely  due  to  the  condensation  of  gasolene  vapor 
which  occurs  before  the  engine,  etc.,  is  properly  warmed  up. 
and  to  the  volatilization  of  unsuitable  lubricating  oil  used 
in  excess  in  the  cylinders,  or  to  its  unsuitable  quality.  Refer 
to  articles  69  and  70. 


xii  INTRODUCTION" 

tances  only  steam  and  gasolene  cars  are  at  present  avail- 
able; and,  for  reasons  which  will  be  explained  later, 
comparatively  few  of  the  former  are  now  running. 
Thus  the  gasolene  engine  is  used  in  the  great  majority 
of  cars  now  running,  to  say  nothing  of  the  enormous 
and  rapidly  increasing  number  of  motor  bicycles  now 
in  use,  in  which  the  motive  power  is  the  gasolene  en- 
gine. This  doubtless  accounts  for  the  kind  of  motor 
language  that  is  heard  at  every  turn,  and,  if  the  truth 
must  be  known,  by  the  boy  in  the  school;  for,  strangely 
enough,  the  schoolboy's  allegiance  to  the  locomotive  has 
been  wavering  in  favor  of  the  automobile  for  some  time, 
and  now  his  school-locker  generally  contains  a  rare  col- 
lection of  pictures,  plates,  post  cards,  technical  journals, 
and  parts  of  models  relating  to  autocars  and  motor 
bicycles,  instead  of  such  things  concerning  the  various 
types  of  locomotives  that  were  formerly  so  much  in 
favor;1  indeed,  it  is  often  astonishing  to  see  what  an 
amount  of  intelligent  interest  all  kinds  of  people  take 
in  the  arrangement  and  working  of  motor  vehicles. 
This  is  particularly  displayed  whenever  a  car  is  stopped 
in  a  public  street,  and  its  hood  is  lifted  for  a  moment 
or  two;  the  usual  crowd,  which  seems  to  spring  from 
the  road  itself,  immediately  surrounds  the  car,  and 
much  advice,  more  or  less  pertinent,  is  freely  offered, 
and  although  the  unhappy  motorist  may  not  profit 
much  by  it,  he  cannot  fail  to  be  impressed  with  the 
growing  knowledge  the  "man  in  the  street"  has  of 
autocar  matters.  Of  course,  this  knowledge  is  in  most 
cases  very  superficial  and  unsound,  and  requires  to  be 
organized  and  supplemented  by  a  good  grasp,  or  at 
least  a  rudimentary  knowledge,  of  the  principles  which 
underlie  and  govern  the  construction  and  working  of 
the  motor,  before  it  is  of  any  practical  use.  So  the 
author,  in  arranging  the  articles  in  this  little  work,  has 

1  In  this  connection  there  cannot  be  a  doubt  that  the  great 
progress  we.  are  making  in  automobilism  has  had  not  a  little 
to  do  with  the  astonishing  increase  in  the  number  of  boys 
whose  greatest  ambition  is  to  become  engineers. 


INTEODUCTION  xiii 

endeavored  to  explain  in  simple,  and  as  far  as  possible 
in  non-technical,  language  the  principles  of  construc- 
tion and  working  that  every  potential  motorist  and 
driver  should  be  acquainted  with  before  he  attempts  to 
drive  a  car  upon  the  road. 


MOTORS  AND  MOTORING 


THE   CHOICE    OF   A    CAE 

2.  The  matter  of  the  selection  of  a  car  is  one  on  which 
it  is  practically  impossible  to  give  any  adequate  advice. 
The  prospective  buyer,  if  he  be  wise,  will  have  looked 
over  the  field  very  carefully  before  he  comes  to  a  final 
decision.  Some  idea  of  the  range  of  power,  price,  and 
kind  of  cars  that  are  now  upon  the  American  market 
may  be  formed  by  a  study  of  the  various  periodicals  de- 
voted to  the  automobile  sport  and  industry.  At  the 
show  in  the  Madison  Square  Garden  at  New  York  last 
winter  there  were  exhibited  between  two  and  three  hun- 
dred makes  of  American  cars.  The  New  York  Import- 
ers' Salon  showed  about  fifty  different  designs.  These 
cars  ranged  from  three  and  a  half  and  four  horse  power 
machines,  costing  $375,  up  to  the  forty,  fifty,  and 
sixty  and  even  ninety  horse  power  cars,  some  of  which 
cost  as  high  as  $15,000.  A  pretty  good  idea  of 
price  may  be  derived  from  the  saying  that  a  motor  car 
costs  $100  a  horse  power  and  $1  a  pound.  There 
are  exceptions  to  this  rule — machines  of  sixteen  and 
eighteen  horse  power,  quoted  at  under  $1,000 — but 
it  represents  the  average.  Of  the  cars,  American  and 
foreign,  now  on  the  market,  ninety  per  cent,  are  pro- 
pelled by  the  gasolene  explosive  engine.  Makers  seem 
to  be  fairly  evenly  divided  as  to  the  merits  of  bevel  and 
chain  driving.  The  desire  for  greater  power  has  forced 
most  of  the  American  makers  to  place  on  the  market 
four-cylinder  cars,  but  these  are  of  necessity  compara- 
tively high  priced,  and  for  light  touring  the  two-cylinder 
and  single-cylinder  cars  are  still  satisfactory.  The  man 
who  knows  what  he  wants,  when  he  buys  a  car,  will 
usually  be  able  to  obtain  reasonable  concessions  from 


2  MOTOKS   AND   MOTORING 

the  dealer.  For  instance,  there  may  be  a  point  or  two 
about  which  he  is  not  absolutely  satisfied.  The  make 
of  carburettor  may  not  be  to  his  liking,  and  he  may  ask 
for  one  of  another  and  higher  grade.  Few  dealers  will 
be  likely  to  let  a  matter  of  this  kind  prevent  a  sale. 


ELEMENTS  OF  A  MOTOR  CAR 

3.  Every  car,  whether  it  be  driven  by  electricity, 
steam,  or  gasolene,  consists  of  two  principal  parts, 
namely,,  the  carriage  body  and  the  chassis.'1  The  for- 
mer is  practically  complete  in  itself;  the  latter  em- 
bodies the  following  principal  elements:  the  frame,  to 
which  the  motor  proper  and  its  accessories  are  attached 
— the  transmission  gear  (including  the  chains  in  chain- 
driven  cars) — axles,  springs,  road  wheels,  steering  gear, 
etc. 

A  complete  car,  with  all  its  fittings  and  accessories, 
appears  to  most  novices  a  very  complicated  vehicle,  but 
when  it  is  carefully  examined,  and  the  function  of  each 
element  and  fitting  understood,  it  really  is  often  a 
fairly  simple  machine;  particularly  is  this  so  in  cars 
that  have  not  been  overloaded  with  refinements  and 
fittings  of  doubtful  utility.  It  has  frequently  been 
remarked  that  the  general  appearance  of  a  car  (with 
the  exception  of  an  electric  one)  is  often  no  sure  indi- 
cation of  the  arrangement  of  its  component  parts,  or 
the  type  of  its  motor,  as  makers  have,  with  very  few  ex- 
ceptions, adopted  the  outward  form  that  everyone  is 
familiar  with,  and  to  accomplish  this  have  even,  in  some 
cases,  put  on  dummy  fittings  and  accessories.  This  ten- 
dency is  particularly  noticeable  where  a  characteristic 
feature  of  some  famous  car  is  so  imitated  that  at  first 
sight  it  is  not  easy  even  for  an  expert  to  name  the 
maker.  It  is  a  practice  much  to  be  deprecated,  more 
particularly  as  some  of  the  designers  who  have  thus 

lrThis  French  word  has  become  Anglicized.  ID  France, 
when  strictly  used,  it  means  the  frame  only. 


MOTOKS   AND   MOTORING  3 

sinned  have  produced  cars  of  such  excellence  that  they 
should  well  be  able  to  hold  their  own  without  such  ad- 
ventitious assistance.  On  the  other  hand,  for  obvious 
reasons,  there  is  much  to  be  said  in  favor  of  co-ordinat- 
ing in  new  cars,  as  far  as  is  practicable,  the  driving  fit- 
tings and  arrangements  (more  particularly  the  pedals 
and  brake  levers),  with  those  which  are  considered  best 
arranged  on  the  leading  cars.  It  will  now  be  convenient 
to  give  some  detailed  attention  to  the  various  elements 
of  the  gasolene  car,  commencing  with  the  motor. 


THE   GASOLENE  MOTOR 
Elements  of  the   Complete  Engine 

4.  As  has  been  explained  in  footnote  1  to  page  xii,  the 
word  motor,  when  strictly  used,  refers  to  the  engine 
which  drives  the  car  or  cycle;  but  as  the  term  is  often 
very  loosely  used,  even  by  experts,  who  of  course  know 
exactly  what  they  are  talking  about  and  to  what  they 
refer,  it  will  be  well  to  make  clear  that  for  our  purpose 
the  gasolene  motor  will  be  considered  to  be  the  complete 
working  engine,  one  that  could  either  be  used  to  drive 
a  car,  a  boat,  or  any  other  machine,  such  as  a  lathe, 
where  power  is  to  be  transmitted  to  some  rotating  part. 
That  is  to  say,  the  motor  must  embody  the  engine 
proper,  and  such  auxiliaries  as  the  carburettor,  induc- 
tion coil,  accumulator,  etc.  The  engine  proper,  as  we 
have  called  it,  is  diagrammatically  represented  by  Figs. 
2  to  5.  It  is  often  referred  to  as  the  Motor;  so  to  be 
clear  on  this  point,  before  we  further  proceed,  it  must 
be  understood  that  when  we  use  the  word  Motor  the 
complete  system  is  referred  to.  Needless  to  say,  this 
explanation  is  given  to  prevent  that  confusion  of 
thought  and  meaning  which  too  often  hamper  the  prog- 
ress of  the  tyro  who  is  studying  the  internal  economy  of 
the  Motor  Car.  The  first  lesson  in  the  art  and  pastime 
of  motoring  might  very  appropriately  be  a  brief  descrip- 


4  MOTOBS    AND   MOTORING 

tion  of  the  Gasolene  Motor,  and  to  facilitate  this  the 
author  has  made  a  diagrammatic  sketch  (Fig.  1)  of 
what  may  be  called  the  complete  system,  which  shows 
the  engine  in  relation  to  the  subsidiary  elements  of  the 
complete  motor.  Obviously,  the  component  parts  are 
arranged  in  such  a  way,  in  relation  to  one  another,  as  to 
show  at  a  glance  their  interdependence,  and  enable  the 
beginner  to  get  a  grasp  of  the  principles  which  govern 
the  working  of  the  machine;  this  means  that  all  the 
parts  must  be  arranged  in  the  same  plane,  and  some  of 
them  made  to  appear  larger  than  they  would  be  if  they 
were  drawn  to  scale.  In  other  words,  we  have  a  dis- 
torted sketch,  showing  the  elements  spread  out  for 
ready  inspection ; x  and  a  careful  examination  of  the 
figure  will  enable  the  reader  to  become  familiar  with 
the  technical  names  of  the  most  important  elements, 
details,  etc.,  which  will  greatly  assist  him  in  under- 
standing the  description  of  the  motor  which  is  to 
follow. 

1  It  should  be  hardly  necessary  to  explain  that  for  a  fixed 
position  of  the  engine  on  the  frame  of  the  car,  the  auxiliary 
elements  of  the  motor  can  be  fixed  in  an  infinite  number  of 
positions  in  relation  to  one  another,  so  long  as  they  are 
connected  up  as  shown  in  the  figure. 


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MOTORS   AND   MOTORING  7 

DESCRIPTION  OF  THE  GASOLENE  MOTOR 
Or  "Internal-Combustion  Engine" 

5.  As   has   been   explained,  the   motor,  although   an 
element  of  the  car,  is  a  complete  heat  engine,  consisting 
of  a  number  of  elements  ingeniously  arranged  in  rela- 
tion to  one  another  to  form  a  whole  working  machine, 
in  which  the  potential  energy  of  the  gasolene  is  con- 
verted into  moving  energy  at  the  crank-shaft    (C.S., 
Fig.  1).    All  gasolene  engines  in  general  use  are  recip- 
rocating ones,  that  is  to  say,  the  straight  line  motion 
of  the  piston  (P.,  Fig.  1)  is  converted  into  the  circular 
motion  of  the  crank-shaft  by  means  of  a  connecting-rod 
(C.R.,  Fig.  1)  and  crank  (CK.,  Fig.  1).    Now,  every 
single  cylinder  reciprocating  engine  must  be  fitted  with 
a  fly-wheel,1  fixed  to  the  crank-shaft,  to  carry  the  crank 
over  the  dead-center ; 2  but  in  the  gas  engine  this  wheel 
has  also  another  function  to  perform,  which  can  better 
be  explained  after  we  have  made  clear  what  goes  on  in 
the  cylinder  during  the  engine's  complete  cycle. 

THE  OTTO   CYCLE 

6.  The  gasolene  motor  is  an  "internal-combustion 
engine,"  that  is  to  say,  one  in  which  a  mixture  of  gaso- 
lene vapor  and  air,  automatically  made  in  an  element 
called  the  carburettor   (by  the  action  of  the  engine), 
in  such  proportions  as  to  form  an  explosive  mixture,  is 
drawn  into  the  cylinder  by  the  engine  itself  and  elec- 
trically ignited,  causing  combustion  to  occur,  and  the 

'This  wneel  is  not  shown  on  the  diagram;  it  generally 
also  forms  the  outer  shell  of  the  friction  clutch.  In  cycle 
motors  the  fly-wheel  and  crank  are  usually  combined. 

2  When  the  crank  and  connection  rod  come  into  the  same 
straight  line,  obviously  no  pressure  on  the  piston,  however 
great,  could  cause  the  crank-shaft  to  turn,  but  by  fixing  a 
fly-wheel  to  the  crank-shaft,  the  momentum  given  to  it 
during  the  working  stroke  of  the  piston  carries  the  crank 
over  the  dead-center,  as  it  is  called. 


8  MOTORS   AND   MOTORING 

piston  to  be  pushed  down  with  great  force  by  the  pres- 
sure of  the  burning  and  expanding  gases,  this  pressure 
on  the  piston  being  transmitted  through  the  connecting 
rod  to  the  crank-shaft. 

The  series  of  operations  which  take  place  in  the 
cylinder  to  form  a  complete  cycle  correspond  to  four 
strokes  of  the  piston  and  two  revolutions  of  the  crank- 
shaft, and  these  operations  make  up  what  is  called  the 
Otto  cycle,  after  Dr.  Otto,1  who  introduced  it  in  1876 
in  his  "  Silent "  gas  engine. 


THE  FOUR  STROKES 

An  examination  of  Figs.  2  to  5  (which  have  been 
drawn,  with  the  positions  of  certain  parts  slightly 
altered,  so  that  each  essential  detail  can  be  seen  quite 
distinctly,  to  conveniently  illustrate  this  description) 
will  enable  the  reader  to  be  clear  about  what  occurs 
during  each  stroke. 

1st.  The  Suction  or  Charging  Stroke  (Fig.  2). — 
During  the  first  out-stroke  of  the  piston  a  partial 
vacuum  is  formed,  and,  the  piston  acting  as  a  pump,  the 
explosive  mixture  is  drawn  into  the  cylinder  through 
the  inlet  valve,  the  spring  of  which  is  only  sufficiently 
strong  to  hold  up  the  valve  on  its  seat. 

2nd.  The  Compression  Stroke  (Fig.  3). — During  the 
return  or  in-stroke,  both  the  inlet  and  exhaust  valves 
are  closed,  and  the  explosive  mixture,  which  was  drawn 
in  during  the  previous  stroke,  is  compressed  by  the 
piston  into  the  clearance  space  (or  combustion  cham- 
ber). 

1The  four-stroke  cycle  was  first  suggested  by  Beau  de 
Rochas  in  1862,  but  the  gas  engine  invented  by  Dr.  Otto, 
and  made  by  Crossley  Brothers,  first  established  the  econ- 
omy and  efficiency  of  internal-combustion  engines  working 
on  this  cycle.  The  invention  was  the  subject  of  a  patent 
granted  in  1876,  No.  2081,  to  C.  D.  Abel,  for  improvements 
in  gas  motor  engines  (a  communication  from  abroad  by 
N.  A.  Otto). 


THE  GASOLENE- ENGINE 
DIAGRAMMATIC  DRAWINGS  SHOWING  THE  FOUR  STROKES  OF  THE 


Fig.  2. 


OTTO  CYCLE. 


iHtET  VALVE  OPENED  TOExPLOSIVEMlXTURt  BOTH  VALVES  CLOSED  OURINd 


BY  SUCTION. 


COMPRESSION 


TV  EXHAUST    STROKE 

Fig,  5. 


10  MOTORS   AND   MOTORING 

3rd.  The  Explosion  and  Expansion  Stroke  (Fig.  4). 
— The  compressed  charge  is  ignited  by  an  electric  spark 
(or  an  incandescent  tube1)  after  the  crank  has  just 
passed  the  dead-center;  and  the  pressure,  due  to  the 
heat  energy,  developed  by  the  combustion,  so  rapidly 
rises  that,  before  the  piston  has  appreciably  moved  on 
this  second  forward  or  working  stroke,  it  reaches  its 
maximum,  and  work  is  done  on  the  piston  by  the 
expanding  gases. 

4th.  The  Exhaust  Stroke  (Fig.  5).— When  the  piston 
has  traveled  about  four-fifths2  of  its  working  stroke, 
the  exhaust  valve  is  opened  by  the  cam  on  the  two-to-one 
shaft 3  to  reduce  the  back  pressure  (or  give  release)  ; 
the  exhaust  taking  place  during  this  fourth  stroke  of 
the  cycle,  or  second  return  or  in-stroke;  the  products  of 
combustion  being  discharged  from  the  cylinder,  the 
gases  which  remain  in  the  clearance  space  (or  combus- 
tion chamber)  mingling  with  the  incoming  explosive 
mixture  of  the  next  charge. 

Thus,  it  will  be  seen  that  the  clearance  space  (Fig.  2) 
is  filled  with  the  products  of  combustion  at  about  atmos- 
pheric pressure  when  we  commence  to  trace  the  work- 
ing of  the  engine;  and  the  piston,  whilst  it  compresses 
the  explosive  mixture  and  makes  the  other  strokes,  with 
the  exception  of  the  explosion  one  (the  third),  is  driven 
by  the  energy  stored  in  the  rotating  fly-wheel. 

Strangely  enough,  this  method  of  working  (the  Otto 
Cycle)  has  never  been  equaled  in  efficiency  by  any 
other  the  mechanical  genius  of  the  world  has  been 
able  to  devise.  Up  to  the  time  of  its  introduction,  gas 
engines  were  worked  by  drawing  in  the  charge  during 


1  Refer  to  Article  26  for  information. 

*The  time  of  opening  the  valve  should  vary  with  the 
piston  speed,  being  earlier  the  higher  the  speed. 

8  This  shaft  is  shown  in  Fig.  1.  It  is  connected  with  the 
crank-shaft  by  a  system  of  tooth  wheels,  which  make  the 
cam-shaft  rotate  once,  whilst  the  motor-shaft  rotates  twice ; 
thus  the  exhaust  valve  opens  once  during  every  two  rota- 
tions of  the  crank-shaft 


MOTORS   AJsD   MOTORING  11 

the  first  portion  of  the  stroke,  and  then  firing  it,  the 
work  being  performed  during  the  remaining  portion  of 
the  stroke * ;  but  the  real  and  fundamental  improve- 
ment made  by  Otto  was  the  compressing  of  the  con- 
tents of  the  cylinder  (the  explosive  mixture)  into  the 
clearance  space  at  the  end  before  the  charge  was  fired. 
This  cycle  of  operations  was  new  and  original,  and 
was  founded  upon  true  mechanical  principles.  The 
mode  of  working  is  not  only  admirable  when  examined 
from  a  mechanical  point  of  view,  but  there  is  also 
the  positive  and  direct  gain  of  dealing  with  a  com- 
pressed charge,  instead  of  one  at  atmospheric  pres- 
sure 2  (the  engine  acting  as  its  own  compressing 
pump) ;  for  the  advantage  of  being  able  to  start  at  the 
instant  of  explosion  with  the  compressed  contents  of 
a  whole  cylinder  full  of  explosive  mixture,  instead  of 
the  uncompressed  contents  of  half  a  cylinder,  is  evident 
to  ordinary  apprehension.  Then  it  is  also  claimed  that 
the  residue  of  the  products  of  combustion  remaining 
in  the  cylinder  (the  contents  of  the  clearance  space) 
acts  as  a  cushion  to  moderate  the  effect  of  the  explosion 
upon  the  working  piston.3 

If  we  are  to  maintain,  in  explaining  matters,  some- 
thing approaching  a  sequence,  it  will  be  convenient  to 
now  give  a  little  attention  to  the  valves  of  the  engines. 


VALVES 

7.  In  the  previous  article  we  have  explained  how  the 
inlet  or  induction  valve  (called  automatic  inlet  valve, 

1  The  Lenoir  engine,  patented  8th  February,  1860. 

*  In  recent  years  there  has  been  a  marked  increase  in  the 
pressure  to  which  the  charge  is  compressed  in  gas  engines, 
with  a  corresponding  increase  of  efficiency. 

3  There  is  much  to  be  said  for  and  against  this  practice. 
A  fresh  mixture  of  gasolene  vapor  and  air  does  not  easily 
mix  with  the  burnt  gases ;  probably  stratification  more  or 
less  occurs.  We  shall  further  touch  upon  this  matter  in 
connection  with  governing. 


12  MOTORS   AND   MOTORING 

and  abbreviated  to  A.I.V.)  is  automatically  opened  by 
the  suction  action  of  the  piston  in  the  first  stroke, 
being  just  kept  on  its  seat  at  other  times  by  the  action 
of  a  weak  spring ; x  on  the  other  hand,  we  have  seen 
that  the  exhaust  valve  was  mechanically  operated  or 
lifted  by  a  cam  fixed  on  the  half-speed  or  two-to-one 
shaft,  the  valve  being  spring  closed.  Now  the  auto- 
matic working  of  the  inlet  valve,  although  simple,  and, 
under  ordinary  conditions  of  working,  very  effective, 
is  not  scientifically  sound,  particularly  for  high  speeds, 
as  the  clearance  space  at  the  commencement  of  the  first 
stroke  is  full  of  the  burnt  gases  above  atmospheric 
pressure,  due  to  the  back  pressure  from  the  silencer; 
therefore,  when  the  piston  begins  its  suction  stroke, 
these  gases  have  to  expand  before  the  fresh  mixture 
can  be  drawn  in  by  the  piston ;  hence  the  sluggish  action 
of  the  valve  in  opening,  just  when  it  should  be 
promptly  responding  to  the  invitation  to  move  given 
by  the  piston  when  it  commences  its  stroke;  indeed, 
in  high-speed  motors  the  valve  should  have  a  slight 
lead — that  is,  should  open  just  before  the  commence- 
ment of  the  stroke,  thereby  facilitating  the  scavenging  2 

1  This  spring  must  be  perfectly  adjusted,  for  correct  work- 
ing.    If  too  weak,  the  valve  will  not  close  rapidly  enough  to 
prevent  the  escape  of  explosive  mixture  on  the  commence- 
ment of  the  compression  stroke,  and  will  subsequently  close 
with  violent  impact  on  its  seat ;  with   such  a  spring  the 
motor  might  be  run  very  slowly,  but  it  would  be  qiiite  use- 
less for  high  speeds.     On  the  other  hand,  if  the  spring  be 
too  strong,   it  does   not   allow   the   valve  to  open   readily 
enough,  or  to  its  full  extent,  to  allow  a  full  charge  of  mix- 
ture  to   enter,   and   the   power  of   the  motor   is   therefore 
reduced.     A  common  practice  is  to  arrange  the  spring  so 
that  an  air  pressure  of  one  pound  per  square  inch  will 
open  it,  but  to  get  the  best  results  the  tension  of  the  spring 
should  be  made  adjustable.     Spare  springs  are  usually  sup- 
plied long  enough  to  allow  them  to  be  cut  away  bit  by  bit 
till  the  valve  closes  with  a  light  beat. 

2  Sweeping  out  some  of  the  residual  burnt  gases  from  the 
previous  charge,   and  thereby  allowing  a  greater  quantity 
of  mixture  to  enter  the  cylinder  every  charge,  and  in  so 
doing  increasing  the  power  of  the  engines. 


MOTORS   AND   MOTORING  13 

of  the  combustion  chambers  (clearance  space).  More- 
over, the  effect  of  the  inertia  of  the  valve  becomes  more 
pronounced  as  the  speed  of  the  engine  increases,  and 
the  volume  of  intake  suffers,  whilst  the  metallic  noise 
of  the  valve  beating  on  its  seat  is  objectionable.  So, 
primarily  for  these  reasons,  makers  have  for  some  time, 
in  increasing  numbers,  been  fitting  motors  with  me- 
chanical operated  inlet  valves  (abbreviated  to  M.O. 
I.V.),  or  worked  in  the  same  way  as  the  exhaust  valves 
from  a  half-speed  shaft.1  This  enables  the  time  of 
opening  and  closing  of  the  valve  to  be  arranged  with 
mathematical  precision,  and  (should  it  be  thought 
desirable)  the  valve  to  remain  open  a  shade  after  the 
piston  commences  the  compression  stroke,  so  that  the 
momentum  of  the  entering  mixture  may  slightly  add 
to  the  charge,  before  the  piston  on  its  change  of  stroke 
has  converted  the  slight  vacuum  in  the  cylinder  to  a 
pressure  above  atmospheric. 

In  strictly  examining  the  relative  merits  of  these  two 
arrangements,  we  ought  to  take  into  account  the  effi- 
ciency of  the  carburettor  that  is  used  in  conjunction 
with  each;  but  for  our  present  purpose  it  will  suffice 
to  point  out  that  in  the  M.O.I.V.  a  continuous  flow  of 
mixture  can  be  relied  upon  for  a  definite  movement  of 
the  piston,  if  the  carburettor  is  capable  of  satisfactorily 
carburetting  a  sufficient  quantity  of  air  to  keep  pace 
with  the  protracted  draw  upon  it,  due  to  the  longer 
time  the  valve  remains  open,  as  compared  with  an 
automatic  one,  for  the  latter  cannot  leave  its  seat  till 
the  vacuum  in  the  cylinder  is  good  enough  to  cause  the 
spring  to  extend;  the  valve  then  suddenly  opens,  when 
a  considerable  inrush  of  mixture  occurs,  but  the  valve 
does  not  remain  unclosed  during  the  completion  of  the 
suction  stroke,  but  rapidly  flutters  or  pulsates  on  and 
off  the  seat  (in  a  way  everyone  can  understand  who  is 
familiar  with  the  behavior  of  springs)  till  the  end 

1  In  some  motors  the  same  shaft  operates  both  valves, 
but  the  more  general  arrangement  is  a  separate  shaft  each 
side  of  the  engine. 


14  MOTOES   AND   MOTORING 

of  the  stroke  is  reached ; *  consequently  the  demand  on 
the  carburettor  is  intermittent,  and  therefore  less 
exhausting  than  in  the  other  case. 

Makers  have  from  time  to  time,  in  acceding  to  the 
demand  for  mechanically  operated  valves,  met  with  a 
good  deal  of  trouble  before  they  have  reached  satisfac- 
tory results;  but  the  conditions  which  must  be  satisfied 
are  so  well  understood  now,  that  there  is  no  difficulty 
in  producing  engines  fitted  with  mechanically  operated 
valves  that  are  highly  efficient,  and  are  connected  to 
carburettors  adapted  to  their  peculiar  needs.  Such 
valves  are  made  interchangeable  with  the  exhaust 
valves;  they  never  stick  or  become  sluggish  in  working 
through  oil  or  other  foreign  matter  clogging  the  valve 
or  its  stem,  and  with  them  the  engine  at  slow  speeds 
is  more  easily  controlled,  their  use  involving  a  mere 
repetition  of  the  cam  gear  required  for  the  exhaust 
valve. 

Of  course  this  slight  complication  is  not  in  their 
favor,  but  in  the  best  cars  the  design  and  workmanship 
are  so  excellent  that  they  give  no  trouble;  indeed,  this 
is  a  case  where  some  sacrifice  of  simplicity  can  be 
safely  made  for  increased  efficiency  and  flexibility.2 

8.  Leaky  Valves. — A  fruitful  source  of  trouble  and 
loss  of  efficiency  in  the  gasolene  motor  is  leaky  valves. 
The  burning  and  erosive  effect  of  the  hot  gases  (par- 
ticularly if  an  exhaust  valve  has  been  held  off  its  seat 
by  dirt),  and  hammering  of  valves  on  their  seats,  must 
sooner  or  later  lead  to  a  sensible  amount  of  wear  occur- 
ring, both  on  valves  and  seats,  even  when  the  materials 
are  just  as  perfect  as  it  is  possible  to  make  them;  but 
this  legitimate  wear  is  greatly  increased  in  cases  where 
the  materials  are  too  soft,  or  are  in  some  other  respects 
unsuitable.  Of  course,  if  this  wear  took  place  with 

aThis  action  causes  the  actual  working  area  to  be  only 
about  half  what  it  would  be  if  the  opening  remained  con- 
stant, so  that  the  A.I.V.  is  larger  than  a  M.O.I.V. 

2  Some  engineers,  whose  opinions  are  entitled  to  respect, 
prefer,  on  the  whole,  the  A.I.V. 


MOTOKS   AND   MOTOKING  15 

absolute  uniformity,  without  the  surface  departing  from 
its  true  form,  there  is  no  reason  why  leakage  should 
occur,  but  in  practice,  after  a  certain  amount  of  wear, 
all  valves  leak,  it  being  only  a  matter  of  degree ;  indeed, 
should  the  power  of  the  motor  diminish,  and  there  is 
reason  to  suppose  that  it  is  due  to  leaky  valves,  the 
valves  should  be  examined,  and  if  there  is  any  doubt 
about  an  inlet  one,  the  spare  valve  (which  should 
always  be  carried  as  part  of  the  equipment)  should  be 
put  in  to  replace  it,  and  the  old  one  can  be  examined 
and  reground,  if  necessary,  at  home.  The  effect  of 
leaky  valves  is  at  once  felt,  as  during  the  compression 
stroke  the  mixture  is  forced  through  them,  so  that  there 
is  a  smaller  charge,  and  a  full  pressure  cannot  be 
reached. 

9.  Grinding  in  Valves  is  an  operation  that  had  better 
be  left  to  the  trained  mechanic  to  perform,  but  cases 
occasionally  occur  where  one  is  not  available,  and  many 
owners  of  cars  like  to  be  able  to  do  these  little  jobs 
themselves,  or  at  any  rate  to  know  how  they  are  done. 
So  a  few  words  relating  to  them  will  not  be  out  of 
place.  Now,  if  the  valve  is  merely  inclined  to  stick,  it 
should  be  well  washed  out  with  gasolene,  which  will  clear 
it  of  any  bad  oil  or  dirt.  If,  on  the  other  hand,  it 
requires  grinding,  it  will  be  found  that  the  conical  or 
mush-room  valve  has  a  groove  cut  on  its  upper  part  to 
fit  a  screw-driver,  or  screw-driver  bit  that  can  be  worked 
with  a  drill  brace.  The  grinding  material  is  a  paste 
made  of  oil  and  fine  sharp  emery  powder,1  and  the  seat 
of  the  valve  should  be  smeared  with  this,  and  the  valve 
turned  to  and  fro  on  its  seat  with  the  screw-driver  or 
brace,  being  taken  off  occasionally  and  the  face  re- 
smeared  to  prevent  grooving.  This  tedious  operation 
must  be  continued  until  both  surfaces  present  a  bright 
and  even  appearance,  without  inequalities  past  which 
gas  could  escape.  A  piece  of  cotton  waste  should  be 

1  Meteoric  Knife  Polish  is  a  preparation  of  emery  powder, 
and  will  do. 


16  MOTOKS   AND   MOTOEING 

carefully  placed  to  prevent  any  of  the  powder  or  dirt 
getting  into  the  cylinder. 

10.  Valve  Lifter. — To  enable  a  motor  bicycle  to  be 
freely  pushed  along  or  pedaled  when  the  engine  is  not 
working,  it  is  necessary  to  open  the  exhaust  valve  to 
prevent  the  motor  being  converted  into  an  air-compres- 
sor, for,  obviously,  a  good  deal  of  work  would  have  to  be 
done  by  the  cyclist  on  the  machine  in  giving  motion 
to  the  piston  during  the  compression  stroke.1     So,  to 
obviate  this,  motor  bicycles   are  fitted  with  a  device 
called  a  Valve  Lifter,  by  means  of  which  the  exhaust 
valve  may  be  kept  permanently  lifted  at  the  driver's 
will.     This  fitting  enables  him  to  start  the  engine  by 
walking  the  bicycle  and  suddenly  letting  go  the  lifter 
after  the  fly-wheel  has  had  given  to  it  enough  mo- 
mentum to  perform  the  compression  stroke.     Skillful 
use  of  this  lifter  when  on  down  grades  will  have  a 
cooling  effect  on  the  cylinder   (which  often  tends  to 
become  too   hot   for   satisfactory  working),   cool   air2 
being  drawn  into  the  cylinder  through  the  exhaust  pipe 
from  the  muffler  each  two  revolutions  of  the  engine. 
The  only  objection  to  this  convenient  expedient  is,  that 
the  air  in  passing  through  the  muffler  tends  to  carry 
with  it  any  dirt  or  dust  that  may  be  in  it. 

When  using  the  lifter,  care  must  be  taken  to  cut  off 
the  spark,  or  explosions  will  occur  in  the  muffler. 

We  may  now  proceed  to  describe  the  nature  of  the 
explosive  mixture,  and  how  it  is  produced  ready  for 
use  in  the  cylinder. 

CARBURATION  AND  CARBURETTORS 

11.  If  the  odor  of  escaping  gas  be  detected  in  a  house, 

'Of  course,  the  whole  of  this  work  is  not  lost,  as  some 
of  it  is  recovered  during  expansion. 

2  After  the  engine  has  been  running  the  muffler  becomes 
very  hot,  and  therefore  the  first  few  charges  of  air  which 
pass  into  the  cylinder  when  the  lifter  is  used  are  warmer 
than  the  outside  air. 


MOTOES    AND   MOTOKING  17 

it  is  proverbial  that  the  ordinary  householder  will  seek 
for  the  leak  with  a  lighted  candle,  too  often  with  a 
result  that  everyone  has  heard  of  and  no  one  seems  to 
profit  by.  In  such  cases  the  escaping  gas  mingles  with 
the  air  in  the  room  and  carburates1  it,  as  it  is  called; 
that  is  to  say,  the  carbon  and  hydrogen  of  the  gas,  of 
which  it  nearly  wholly  consists,  become  rapidly  dif- 
fused in  the  air,  the  oxygen  of  which  forms,  or  tends  to 
form,  with  the  hydrocarbon  gas,  an  explosive  mixture 
which  only  requires  igniting  to  cause  an  accident.2 

Now  the  explosive  mixture  we  use  in  the  gasolene 
motor  consists  of  air  carburetted  by  the  vapor  of  gaso- 
lene,3 and  the  apparatus  used  to  prepare  or  form  this 
mixture  is  called  a  carburettor,  a  fitting  that  appears 
in  a  great  variety  of  forms;  indeed,  a  month  rarely 
passes  without  the  pages  of  our  admirable  motor  jour- 
nals being  adorned  with  some  new  device,  which  more 
or  less  differs  from  existing  ones.  There  is  nothing 
astonishing  about  this  when  it  is  understood  how  easily 
a  mixture  can  be  made,  for  everyone  has  noticed  how 
quickly  a  little  Eau  de  Cologne  vaporizes  when  applied 
to  the  hands  or  face.  The  same  thing  occurs  with 
gasolene;  it  is  an  exceedingly  volatile  spirit,  rapidly 
evaporating,  as  all  spirits  do  when  exposed  to  the  air, 
and  this  action  is  much  increased  by  the  application 
of  heat,  but  it  does  not  require  any  preliminary  heating 

1When  air  is  impregnated  with  carbon,  it  is  said  to  be 
carburetted  or  carburized. 

2  It  is  instructive  to  note  that  a  mixture  of  this  kind  may 
be  either  too  weak  or  too  strong  to  explode,  as  for  complete 
combustion  about  6.3  volumes  of  air  to  1  of  gas  are  required ; 
but  the  range  of  ignition  appears  to  be  about  1  of  gas  to  5 
of  air,  to  1  of  gas  to  13  of  air.    And  so,  in  the  cylinder  of 
the  motor,  we  may  have  a   charge  which  consists  of  too 
much  air,  or,  the  more  usual  case,  one  that  has  been  super- 
carburetted    (one    that    is    too    rich    in    gasolene    vapor). 
Between   these  extremes  there   is  a  particular  or  critical 
mixture  that  in  any  case  will  be  more  efficient  than  any 
other,  as  we  shall  directly  see. 

3  Gasolene  is  a  hydrocarbon.    Refer  to  article  on  fuel, 
page  28. 


18  MOTOES    AND    MOTOKING 

for  use  in  even  the  smallest  engines.  It  can  be  readily 
vaporized  by  the  simplest  and  crudest  form  of  car- 
burettor, and  this  principally  accounts  for  the  wonder- 
ful flexibility  of  the  gasolene  motor;  indeed,  it  now 
appears  difficult  to  make  a  motor  that  won't  go, 
although  a  few  years  ago,  when  so  many  were  com- 
mencing to  experiment  with  motors  who  were  unac- 
quainted with  matters  relating  to  carburation  and 
ignition,  much  trouble  was  experienced  in  coaxing  them 
into  motion. 

If  an  explosive  mixture  can  be  readily  produced,  it  is 
not  such  an  easy  matter  to  satisfy  all  the  important 
conditions,  for  a  satisfactory  carburettor  *  must  be  capa- 
ble of  regularly  supplying  a  perfectly  adjusted  mixture 
of  gasolene  vapor  (or  atomized  spray)  and  air  to  the 
motor  cylinder  under  all  conditions  of  speed,  load,  and 
temperature ;  it  must  be,  self-adapting,  and  be  able  to 
automatically  and  definitely  carburet  the  air  to  form 
a  mixture  of  an  exactly  predetermined  degree  under 
all  conditions  of  working.  The  very  perfect  speed  con- 
trol, over  a  wide  range,  of  some  of  the  best  known 
motors  is  largely  due  to  these  conditions  being  more  or 
less  satisfied,  and  to  a  well-governed  throttle 2  and  an 
adjustable  ignition.3 

12.  The  Float-Feed  Carburettor.— The  type  of  car- 
burettor that  has  survived  all  others,  owing  to  its  sim- 
plicity and  absolute  automatic  action,  is  the  float-feed 
one  or  spray  kind,  shown  in  Fig.  6,  which  shows  the 
principal  features  of  the  class  of  carburettor  to  which 
it  belongs.  An  atomizing  nozzle  N  (whose  size  is  care- 

1  Most    carburettors    on    large   cars    are    fitted    with    hot 
jackets  for  use  in  cold  weather,  as  will  be  explained,  the 
heat  of  the  engine  itself  sufficing  in  other  cases. 

2  When  a  motor  is  governed  by  throttling  or  reducing  the 
quantity  of  the  charge  of  the  explosive  mixture,  without 
altering  the  proportions  of  air  and  vapor,  it  is  said  to  be 
governed   on   the   throttle.     Refer   to   article   on   governing 
and  controlling  by  throttling  the  mixture,  page  55. 

8  Refer  to  article  on  Advancing  and  Retarding  Ignition, 
page  50. 


MOTOES   AND   MOTORING 


19 


fully  calculated)  is  supplied  with  petrol  from  the  float- 
chamber  FC,  into  which  the  spirit  (gasolene)  flows 
by  gravitation  from  its  tank  through  the  pipe  X,  and 
is  kept  at  a  constant  level  by  a  float  FF,  the  needle 


FLOAT-FEED  CARBURETTOR. 


valve  V  regulating  its  flow;  thus  the  gasolene  is  drawn 
from  the  float-chamber  through  an  exceedingly  fine 
orifice  in  the  nozzle  N,  in  the  form  of  a  spray,  into  the 
mixing  chamber  MM  (pulverization  being  assisted  by 
it  impinging  upon  the  roughened  surface  of  the  fixed 
cone  K  and  becoming  atomized),  where  it  is  carburized 
by  mingling  with  the  air  from  the  inlet  AV  on  its  way 


20  MOTOES   AND   MOTORING 

to  the  cylinder,  the  mixture  being  drawn  through  the 
throttle  valve  T  (as  it  passes  to  the  inlet  valve  of  the 
engine)  by  the  suction  stroke  of  the  piston.  Vaporiza- 
tion of  the  atomized  spray  in  the  mixing  chamber  MM 
is  assisted  by  the  hot  jacket  J,  which  is  heated  by  pass- 
ing through  it  (entering  at  E  and  passing  out  at  0) 
either  hot  water  from  the  cylinder  jacket  or  exhaust 


The  richness  of  the  mixture  is  regulated  either  by 
controlling  the  quantity  of  the  gasolene  passing  through 
the  nozzle  N,  or  the  quantity  of  air  entering  the  mouth 
AV;  if  by  the  former,  a  valve  G,  operated  by  a  hand 
wheel  W,  varies  the  size  of  the  passage  through  which 
the  gasolene  flows  on  its  way  to  the  nozzle  N ;  and,  if  by 
the  latter,  a  shutter  AV  fitted  with  a  sheet  of  gauze  to 
prevent  any  fluffy  matter  passing  (regulated  by  the  fly 
nuts  RE,  the  stay  S  being  fixed),  controls  the  quantity 
of  air  entering.  This  adjustment  is  made  before  start- 
ing on  a  run,  to  suit  the  condition  of  the  atmosphere; 
the  quantiy  of  air  required  to  make  the  best  mixture 
varying  with  its  temperature  and  pressure,  it  frequently 
happens  that  on  a  hot  day  the  mixture  will  require 
readjusting  in  the  cool  of  the  evening.  Now  to  keep 
the  quantity  of  mixture  constant,  and  to  ensure  the 

lThe  well-known  Longuemarre  carburettor  is  heated  by 
the  exhaust  gas.  In  either  case,  the  flo^  of  fluid  through 
the  jacket  should  be  regulated  by  a  cock  or  plug,  as  when 
too  cold,  the  gasolene  does  not  volatilize  sufficiently,  and 
when  too  hot  it  does  so  to  excess.  As  a  matter  of  fact,  it 
is  only  when  the  atmosphere  is  heavily  charged  with  moist- 
ure, or  when  running  through  keen,  frosty  air,  that  a  heat- 
ing jacket  is  required;  if  such  means  for  regulating  the 
temperature  of  the  jacket  are  not  provided,  the  resultant 
cylinder  charge  is  often  much  richer  than  is  necessary  or 
good  for  the  engine,  causing  the  plugs  and  valves  to  become 
sooty.  When  a  hot  jacket  is  not  used  on  a  carburettor,  it 
is  usual  to  so  fix  the  latter  that  the  air  mouth  is  near 
enough  the  cylinder  for  the  air  entering  the  carburettor 
to  be  previously  warmed ;  indeed,  long,  cold  pipes  should 
never  be  used  to  convey  the  mixture  from  the  carburettors 
to  the  cylinder,  as  the  gasolene  vapor  in  the  mixture  is 
apt  to  condense  when  reduced  in  temperature. 


MOTORS   AND   MOTORING  21 

opening  of  gasolene  valve  G  and  air-shutter  AV,  the  level 
of  the  gasolene  in  the  float-chamber  FC  must  be  unvary- 
ing, and  this  condition  is  satisfied  by  the  action  of  the 
float 1  FF  and  needle,  for  should  the  level  of  the  spirit 
slightly  fall,  the  float  FF  and  attached  needle  would 
descend  with  it,  allowing  the  weights  WW  to  operate 
the  levers  WH,  whose  fulcra  are  at  HTL  This  move- 
ment causes  the  other  ends  of  the  levers  to  move  up- 
wards and  carry  with  them  the  grooved  collar  on  the 
needle,  into  which  they  fit;  this  lifts  the  needle  point 
off  its  seat  and  allows  more  gasolene  to  pass  from  the 
tank  to  the  float-chamber;  this  in  its  turn  lifts  the  float 
and  depresses  the  needle  closing  the  valve,  so  that  the 
float  automatically  maintains  the  level  of  the  gasolene. 
Great  care  must  be  taken  to  pass  the  spirit  through  a 
strainer  in  filling  the  tank.  In  the  best  arrangements 
a  screen  of  fine  gauze  is  placed,  as  at  Q,  to  exclude  any 
dirt  which  may  be  in  the  gasolene,  which,  if  allowed 
to  enter,  would  tend  to  stop  up  the  small  passages,  and 
prevent  the  flow  of  gasolene;  indeed,  such  stoppages  are 
a  fruitful  source  of  trouble,  particularly  at  the  nozzle, 
where  dust,  carried  in  by  the  air,  is  apt  to  give  trouble.2 
Should  the  screwed  bung  which  is  generally  used  to 
stop  the  filling-hole  in  the  gasolene  tank  get  lost,  it 
should  never  be  replaced  by  a  cork  one,  as  cork-dust 
sooner  or  later  will  find  its  way  into  the  carburettor, 
and  cause  endless  trouble  by  blocking  the  small  pas- 


13.  Auxiliary  Air. — It  would  be  interesting  and  in- 

1  If  great  care  is  not  taken  to  make  the  float  perfectly 
fluid  tight,  the  gasolene  will  penetrate  it  and  cause  it  to 
be  "  water-logged,"  as  it  is  called ;  it  then,  of  course,  ceases 
to  act  as  a  float. 

2  The  usual  expedient  in  this  case,  if  time  will  not  admit 
of   the   carburettor   being   properly   cleaned,   is  to   push   a 
piece  of  fine  wire  through  the  hole  and  twirl  it  round ;  this 
invariably  answers  the  purpose,  but  tends  to  enlarge  the 
hole  and  make  the  mixture  too  rich ;  so,  to  be  on  the  safe 
side,   carburettors  should  be  periodically  taken  apart  and 
thoroughly  cleaned. 


22  MOTOES   AND   MOTOKING 

structive  to  go  into  all  the  points  which  must  be  con- 
sidered in  deciding  how  the  degree  of  carburation 
should  vary  with  different  temperatures,  atmospheric 
pressures,  speeds  and  other  conditions  of  running,  but 
space  will  not  admit  of  this,  and  it  must  suffice  to  point 
out  that  the  practice,  which  is  found  to  give  excellent 
results  with  this  type  of  carburettor  in  maintaining 
a  uniform  mixture,  is  to  admit  what  is  called  auxiliary 
air  to  the  mixing  chamber  (to  mingle  with  the  mixture 
and  reduce  its  richness),  when  the  engine  is  running 
fast  and  the  vacuum  is  good.  The  air  is  admitted 
through  the  auxiliary  air-valve  AAV,  which  is  fitted 
with  an  adjustable  spring  Z  (so  that  its  strength  may 
be  adjusted  to  give  the  best  results),  and  when  the 
suction  is  strong  enough,  this  valve  is  forced  open  by 
the  air  outside,  against  the  action  of  the  spring,  and 
extra  air  flows  in  and  mingles  with  the  mixture.  Now, 
let  us  try  and  be  clear  why  this  extra  air  is  required.1 
To  do  this,  we  must  realize  that  during  a  rapid  suction 
stroke,  air  and  gasolene  are  being  drawn  through  the 
openings  AV  and  nozzle  N  respectively,  at  a  high 
velocity;  at  the  end  of  the  stroke  the  inlet  valve  of  the 
engine  cylinder  suddenly  closes,  and  no  further  mix- 
ture can  enter.  This  means  that  the  flow  of  air  through 
AV  almost  immediately  stops;  but  not  so  the  gasolene, 
as,  due  to  its  much  greater  density  and  inertia,  it  con- 
tinues to  flow  into  the  mixing  chamber  M,  and  would 
make  the  mixture  much  too  rich  to  give  a  good  result 
in  the  cylinder  were  it  not  for  the  extra  air  entering 
by  the  auxiliary  valve.  Again,  as  the  engine  slows 
down,  let  us  say,  due  to  throttling  (partly  closing  the 
throttle  valve  T),  there  is  a  greatly  reduced  suction 
(not  enough  to  open  the  auxiliary  air-valve),  and 
although  air  may  be  freely  entering  at  AV,  the  gasolene 
will  be  passing  out  of  nozzle  N  in  a  very  sluggish  way, 

xln  some  carburettors,  instead  of  admitting  air  by  an 
auxiliary  valve,  it  is  passed  into  tbe  mixing  chamber  by 
increasing  the  opening  of  the  air  inlet  at  AV  by  a  control 
arrangement. 


MOTORS    AND   MOTORING  23 

and  there  will  be  an  abundance  of  air  in  the  chamber 
to  form  a  proper  mixture,  until  at  a  critical  speed 
of  the  engine  the  suction  will  not  be  strong  enough 
to  draw  gasolene  out  of  the  nozzle,  as  the  normal  level 
of  the  spirit  in  the  nozzle  must  always  be  a  little  below 
the  orifice;  but  this  speed  of  course  the  motorist  soon 
becomes  familiar  with,  and  he  is  careful  to  avoid  touch- 
ing it  if  he  wishes  to  keep  the  motor  running. 

Formerly  (in  the  days  of  the  old  cut-out  governor) 
it  was  not  practicable  to  vary  the  speed  of  the  engine 
very  much,  but  with  the  introduction  of  the  throttle 
control x  which  has  been  so  generally  adopted,  a  great 
amount  of  elasticity  or  flexibility  in  running  became 
possible,  and  now  most  engines  have  a  range  from  about 
200,  or  even  150  revolutions  per  minute  when  throttled, 
to  1500  or  1600  in  some  cases  when  the  throttle  is  fully 
open,  the  amount  of  mixture  used  being  almost  in  pro- 
portion to  the  speed. 

In  many  of  the  carburettors  in  use  (notably  Kreb's), 
great  ingenuity  has  been  displayed  in  devising  them,  so 
that  the  fundamental  condition  for  perfect  working 
may  be  automatically  satisfied,  namely,  the  production 
of  a  constant  degree  of  carburation  at  all  speeds,  so 
that  the  power  of  the  motor  may  be  directly  propor- 
tional to  its  speed.  In  those  carburettors  that  are  not 
fitted  with  such  an  automatic  arrangement,  the  mix- 
ture must  be  made  by  hand.  In  any  case,  the  adjust- 
ment should  be  made  to  enable  the  carburettor  to  take 
in  as  much  air  as  it  possibly  can  whilst  producing  a 
good  mixture,  as  a  faulty  mixture  is  nearly  always  due 
to  an  extravagant  and  wasteful  use  of  gasolene,  with 
all  the  evils  attending  it.2 

The  spray  type  of  carburettor,  largely  owing  to  its 
compactness  and  the  small  amount  of  room  it  takes 
up,  is  also  superseding  the  float  type  for  motor  cycles, 

1  By  the  governor ;  or  the  amount  of  mixture  entering  the 
cylinder  may  be  controlled  by  hand. 

2  Generation  of  steam  in  the  cylinder  jacket,  sooty  plugs, 
loss  of  power,  and  waste  of  fuel. 


24  MOTORS   AND   MOTORING 

although  it  has  the  disadvantage  of  being  easily  flooded 
when  the  machine  is  run  over  a  rough  road,  the  jolting 
allowing  the  gasolene  to  escape  into  the  reservoir  each 
time  the  needle  is  bumped  off  its  seat;  as  a  result,  the 
gasolene  supply-pipe  has  to  be  fitted  with  a  small  cock 
or  valve,  so  that  the  quantity  flowing  can  be  regulated 
by  hand  when  necessary. 

In  starting,  it  is  sometimes  necessary  (owing  to  the 
nozzle  becoming  more  or  less  closed  by  dirt,  and  the 
gasolene  in  it  becoming  stale 1  by  standing)  to  flood  the 
carburettor  and  to  assist  in  forming  a  rich  mixture  by 
spraying  the  spirit  by  hand;  to  do  this,  the  thimble  B 
(Fig.  6)  is  taken  off,  and  the  end  U  of  the  valve  spin- 
dle moved  up  and  down,  an  upward  movement  allowing 
the  gasolene  to  enter  the  float-chamber  from  the  tank, 
and  a  push  downwards  forcing  it  through  the  nozzle. 

14.  Surface  Carburettors. — The  carburettors  that 
were  first  generally  adopted,  and  are  still  used  on  some 
motor  cycles,  were  of  the  surface  type,  an  example  of 
which,  of  the  pattern  used  on  motor  tricycles,2  namely 
the  De  Dion,  is  shown  in  Fig.  7.  Outwardly  it  consists 
of  a  triangular  brass  or  copper  box,  shaped  to  fit  be- 
tween the  tricycle  frame  tubes  and  the  rider's  seat.  In 
the  figure,  one  side  has  been  removed  to  show  the  ar- 
rangement of  the  interior;  a  plate  D,  fixed  to  the  air- 
tube  or  chimney  AT,  divides  the  whole  box  into  two 
parts,  the  lower  forming  a  reservoir  for  the  gasolene,  a 
further  quantity  of  which  is  generally  carried  in  a  cylin- 

1  Gasolene,  when  allowed  to  stand  exposed  to  the  air, 
rapidly  evaporates,  the  most  volatile  part  passing  off  first, 
the  portion  remaining  being  impoverished  or  stale. 

'The  principle  of  the  surface  carburettor  can  be  best 
understood  by  examining  this  pattern.  Those  used  on  bicy- 
cles are  very  much  alike  in  principle  and  general  con- 
struction. In  a  pattern  largely  used  the  air-tube  AT  is 
carried  down  nearly  to  the  bottom  of  the  reservoir  R,  and 
its  lower  part  is  perforated  or  zig-zagged,  so  that  the  air 
bubbles  up  through  the  spirit  instead  of  skimming  its  sur- 
face, and  with  this  arrangement  almost  the  last  drop  can 
be  used,  even  if  it  is  a  little  stale. 


MOTORS   AND   MOTORING  25 

drical  tank  attached  to  the  rear  frame  of  the  machine, 
and  placed  just  above  and  connected  to  the  carburettor 
by  a  pipe.  The  plate  D  is  used  to  prevent  the  spirit 
splashing  into  the  upper  chamber  X  in  the  form  of 
spray,  instead  of  passing  into  it  as  vapor.  The  air 
enters  through  the  air-tube  AT,  and  passes  between  the 

THE  DE  DION  SURFACE  CARBURETTOR. 
X 


Fig.  7. 


plate  D  and  the  gasolene  surface  (which  in  starting  is 
just  below  the  plate)  as  shown,  licking  the  surface,  and 
carrying  with  it  a  charge  of  spirit  vapor  to  the  cham- 
ber X,  on  its  way  to  the  mixing  chamber  or  twin  tap, 
MC.  The  function  of  the  tube  AT  is  to  admit  air  below 


26  MOTORS   AND   MOTORING 

the  plate  D  during  the  suction  stroke  of  the  engine,1  so 
that  it  may  be  diffused  in  the  gasolene  vapor,  as  ex- 
plained, and  be  drawn  through  the  twin  tap  MC,  which 
is  arranged  to  admit  an  adjustable  quantity  of  addi- 
tional air  to  form  a  suitable  mixture  to  enter  the  cylin- 
der through  the  pipe  M.  A  bent  pipe,  LN,  from  the 
engine  exhaust  passes  through  the  lower  part  of  the 
reservoir  to  warm  the  gasolene,  and  to  accelerate  its 
vaporation,  as  evaporation  of  the  spirit  lowers  its  tem- 
perature. F  is  a  float  fixed  to  a  wire  EF,  which  passes 
through  the  air-tube  AT,  the  length  of  the  wire  at  E 
projecting  above  AT  indicating  the  level  of  the  gaso- 
lene in  the  reservoir.  The  most  interesting  and  impor- 
tant feature  of  this  type  is  the  twin  tap  MC,  shown  in 
detail  in  Figs.  8,  9,  and  10,  the  Fig.  8  showing  a  section 
on  line  XX  (Fig.  7),  and  Figs.  9  and  10  being  sections 
taken  through  the  lines  DD  and  EE  (Fig.  8)  respec- 
tively. These  show  how  the  air  lever  A  is  connected  to 
a  hollow  cylindrical  part,  a  half  of  it,  MON,  being  made 
of  wire  gauze,  in  such  a  way  that  a  movement  of  lever 
A  controls  the  quantity  of  rich  mixture  entering  below 
at  K  from  the  chamber  H,  and  the  amount  of  auxiliary 
air  passing  in  from  above  at  J,  the  two  streams  mixing 
in  the  chamber  P  to  form  the  perfected  mixture,  which 
passes  into  the  pipe  M  on  its  way  to  the  cylinder.  A 
movement  of  the  lever  A  (Fig.  10)  to  the  right  increas- 
ing the  opening  for  air,  and  decreasing  the  opening  VN 
for  the  rich  mixture,  so  that  the  quality  of  the  mixture 
can  be  regulated  when  starting  to  give  the  best  results 
for  the  gasolene  used,  and  the  temperature,  pressure, 
and  condition  of  the  atmosphere. 

The  Figs.  8  and  9  show  how  the  gas  lever  G  moves 
the  hollow  cylinder  WY,  which  is  free  to  revolve  in  the 
outer  cylindrical  case,  so  that  it  acts  as  a  throttle  valve, 
giving  the  rider  control  over  the  quantity  of  mixture 
which  passes  into  pipe  M  from  the  mixing  chamber  P 
on  its  way  to  the  cylinder. 

aThe  cap  on  top  of  AT  forms  an  adjustable  shutter,  used 
to  regulate  the  quantity  of  air  entering. 


MOTORS   AND   MOTORING  27 

One  of  the  drawbacks  of  this  carburettor  is  that  it 
takes  up  more  room  than  the  spray  one,  and  it  cannot 

I 


be  used  with  such  heavy  gasolene  as  the  latter  can.     On 
the  other  hand,  it  has  some  advantages  which  perhaps 


28  MOTORS   AND  MOTORING 

have  not  always  been  appreciated  as  they  should  be  for 
small  engines,  particularly  for  motor  bicycles.  Not  the 
least  of  these  is,  it  has  no  very  small  gasolene  holes  to 
get  clogged  with  dirt,  and  throttling  does  not  affect  the 
carburation,  as  it  does  in  many  of  the  simplified  spray 
carburettors,  leading  to  excessive  gasolene  consumption. 


THE  FUEL 

15.  The  fuel  that  is  almost  exclusively  used  by  mo- 
torists in  this  country  is  the  light  petroleum  spirit, 
called  gasolene.     It  possesses  valuable  properties,  which, 
notwithstanding  its  drawbacks,  make  it  at  present  con- 
sidered the  most  suitable  fuel  for  motor  purposes.     It 
is  a  distillate  of  crude  petroleum,  the  various  products 
of  which    (called  fractions  or  cuts)    are  obtained  by 
what  is  known  as  fractional  distillation. 

16.  Straining    and    Filtering    Gasolene. — Compara- 
tively few  motorists  realize  the  necessity  of  carefully 
straining  the  gasolene  as  it  is  poured  into  the  supply- 
tank  of  the  car.     If  they  commence  by  using  a  strainer, 
sooner  or  later  it  will  become  mislaid,  and  the  spirit  is 
poured  into  the  tank  direct  from  the  can ;  in  doing  this, 
they  risk  getting  an  accumulation  of  dirt  in  the  tank, 
which  in  due  course  finds  its  way  into  the  carburettor, 
with  the  inevitable  stoppage,  for,  even  if  the  carburettor 
it  fitted  with  a  disc  of  gauze  within  the  union  below 
the  float-chamber,  as  shown  at  Q  in  Fig.  6,  it  is  only  a 
matter  of  time  for  its  minute  interstices  to  become  com- 
pletely filled,  and  the  flow  of  gasolene  to  be  stopped,  so, 
should  the  strainer  become  mislaid,  one  should  be  im- 
provised.    For  instance,   a  clean  handkerchief   folded 
three  or  four  times  has  been  found  to  be  an  effective 
substitute.     Many  motorists  have  been  troubled  by  a 
kind  of  short  silky  fluff  getting  into  the  union  below 
the  float-chamber;  this  stuff  is  much  too  fine  to  be  ar- 
rested by  the  gauze,  so  something  with  a  much  finer 
mesh  is  required  for  the  strainer;  a  good-sized  piece  of 


MOTOES    AND   MOTOBITO  29 

clean  thin  chamois-skin  has  been  found  effectually  to 
filter  the  spirit  without  unduly  delaying  the  filling  of 
the  tank;  of  course  this  necessitates  the  use  of  a  funnel 
of  large  diameter,  say  some  8  or  9  inches  at  least. 


GASOLENE,  ITS  DISADVANTAGES,  AND  THE 
PBECATJTIONS    TO    BE    TAKEN    IN    USING    IT 

17.  No  one  should  be  entrusted  with  a  can  of  gaso- 
lene who  is  unacquainted  with  some  of  its  properties; 
every  motorist  should  make  a  point  of  learning  what 
liberties  he  may  and  may  not  take  with  it.  It  being  a 
highly  volatile  spirit,  a  naked  light  or  ordinary  lamp 
should  never  be  taken  into  a  place  where  it  is.  stored,  or 
into  a  motor-house;  nor  should  smoking  be  allowed  in 
such  places,  as  a  slight  leak  would  probably  lead  to  an 
accumulation  of  gasolene  vapor,  which  would  be  highly 
dangerous.  On  the  other  hand,  leakage  of  gasolene  on 
a  moving  car  would  cause  no  more  danger  from  explo- 
sion than  a  gas  jet  escaping  for  a  few  minutes  in  the 
open  air,  but  a  fairly  large  quantity  of  gasolene  spilled 
in  the  street  or  in  a  room  would  be  a  cause  of  danger 
from  its  vapor  mixing  with  the  air  and  forming  an  ex- 
plosive mixture,  through  which  a  flame  could  leap  sev- 
eral feet.  Gasolene  spirit  itself  merely  ignites  with  a 
hot  flame,  and  does  not  cause  an  explosion;  indeed,  a 
poker  almost  red-hot  may  be  placed  in  gasolene  without 
its  igniting,  although  a  white-hot  one  would  cause  it  to 
burn;  but  when  gasolene  vapor  mixes  with  about  8  to 
10  times  its  volume  of  air,  a  rich  gas  is  formed,  which 
will  burn  without  exploding;  a  larger  proportion  of  air, 
about  17  or  20  to  1,  forms  an  explosive  mixture. 
Finally,  it  is  dangerous  for  transport  or  storage,  and 
the  risk  is  greatly  increased  in  a  hot  climate,  owing  to 
its  low  flash-point,  as  any  oil  is  dangerous  when  heated 
above  its  flashing-point,  be  that  high  or  low.  Of  course 
the  ideal  light  for  the  motor-house  is  the  electric  light, 


30  MOTOKS   AND   MOTOEING 

but  when  this  is  not  available  a  Davy  lamp  1  should 
always  be  used  when  gasolene  is  under  cover,  to  avoid 
risks,  as  the  conditions  necessary  for  an  explosion  should 
be  assumed  to  always  exist. 

18.  Objectionable  Odor  of  the  Exhaust  Gases.— The 
offensive  odor  of  the  exhaust  gases,  from  most  gasolene 
cars,  is  causing  a  deal  of  unfavorable  comment.     It  is 
bad  enough  for  the  perfume  of  the  sweet-smelling  brier 
in  a  country  lane  to  be  polluted  by  an  occasional  passing 
car,  but  in  our  streets  and  parks,  with  a  succession  of 
passing  cars,  the  nuisance  is  becoming  increasingly  pro- 
nounced, and  all  who  are  interested  in  the  future  of  the 
automobile  should  do  their  best  to  minimize  it.     It  is 
mainly  due  to  exhausting  unburned  fuel,  and  to  the  use 
of  either  an  unsuitable  lubricating  oil  in  the  cylinder, 
or  one  that  may  be  very  good  for  the  purpose,  but  is 
being  used  in  excess.     The  splashing  of  oil  on  the  muf- 
fler, or  on  an  air-cooled  cylinder,  or  other  hot  part,  will 
also  cause  this  trouble.     Briefly,  the  trouble  is  more 
likely  to  occur  in  engines  (a)  fitted  with  un jacketed  car- 
burettors; (&)  with  long  and  large  pipes  connecting  the 
carburettor  to  cylinder;  (c)  at  slow  speeds  than  at  high 
speeds;  (d)  in  small  cylinders  than  in  large  ones;  (e) 
when  starting,  due  to  condensation  of  the  spirit  vapor 
in  the  cylinder,  etc.,  and  it  is  bound  to  occur  whenever 
an  unclean  cylinder  lubricating  oil  of  too  low  flash- 
point is  used. 

19.  Other  Fuels  than  Gasolene. — The  only  other  fuels 
that  could  be  economically  employed  in  internal  com- 
bustion engines  of  the  motor  type  are  benzol  or  benzene, 
a  spirit  distilled  from  coal-tar,  and  technical  or  dena- 
turized  alcohol.  Either  of  these  could  be  used  with  a  little 
modification  of  the  valves,  the  carburettor,  and  the  com- 
pression, and  either  would  appear  to  be  a  cheaper  fuel. 

1  This  lamp  is  surrounded  by  wire  gauze,  so  the  explosive 
gases,  though  they  pass  free  through  the  meshes,  are  so 
cooled  by  contact  with  the  comparatively  cold  metal  and  by 
its  high  radiating  powers,  that  though  they  may  be  burning 
on  one  side  of  the  gauze,  the  combustion  ceases  as  the  gases 
pass  through.  NOTE — Gasolene  vapor  is  heavier  than  air. 


MOTOES   AND   MOTOEING  31 

20.  Air  Required  for  Combustion. — We  have  seen 
that  when  a  charge  of  mixture,  of  gasolene  vapor 
and  air,  is  exploded  in  the  cylinder,  rapid  com- 
bustion or  burning  of  the  gas  occurs,  the  evolution  of 
heat  occurring  as  it  burns  and  expands,  causing  the 
piston  to  be  pushed  forward  with  great  force.  We  must 
now  be  clear  about  the  elementary  chemical  conditions 
which  must  subsist,  if  the  chemical  combination  which 
causes  the  explosion  is  to  be  perfect.  Now,  by  chemical 
analysis  it  is  found  that  gasolene  (hexane  C6H14),  of 
specific  gravity  0.700,  contains  84  per  cent,  of  carbon 
and  16  per  cent,  of  hydrogen,  and  by  the  aid  of  chemi- 
cal equations  we  can  deduce  the  proportion  of  air  re- 
quired to  supply  oxygen  enough  to  mix  with  these 
gases,  in  order  that  when  the  mixture  is  ignited  it  may 
burn  so  rapidly1  as  to  produce  a  sharp  explosion,  no 
gas  remaining  unburnt.  Thus  1  Ib.  of  hydrogen  (H) 
requires  8  Ibs.  of  oxygen  (0)  to  burn  it  (the  product  of 
combustion  being  steam),  and  1  Ib.  of  carbon  (C)  re- 
quires 2§  Ibs.  of  oxygen  to  burn  it  to  carbonic  acid 
(carbonic  dioxide,  C02).  But  the  composition  of  air 
by  weight  is  one  of  oxygen  to  3£  of  nitrogen  (N") 
nearly,  so  for  each  pound  of  oxygen  required  4£  Ibs.  of 
air  must  be  provided.  Then  to  burn  1  Ib.  of  gasolene 
we  must  have  -84X2§X4£=10-18  Ibs.  of  air  for  the  C, 
and  -16X8X4^=5-76  Ibs.  of  air  for  the  H,  or  10-18+ 
5-76=15-94  Ibs.  in  all.  But  if  we  had  taken  the  more 
exact  proportion  of  N  to  0  in  the  air,  this  would  have 
amounted  to  nearly  15  Ibs.  to  burn  1  Ib.  of  gasolene. 
And  as  there  are  13-14  cubic  feet  of  air  to  the  pound,  at 
a  temperature  of  62°  F.,  we  get  15X13-14=197,  as  the 
quantity  in  cubic  feet  chemically  required.  Then  we 
must  not  forget  that  the  hydrocarbon  fuel  is  being 

1The  rapidity  depends  upon  the  pressure  reached  during 
the  compression  stroke.  This  law  applies  to  all  explosives. 
Nobel  found  that  a  pebble  of  gunpowder,  which  took  two 
seconds  for  its  combustion  in  free  air,  was  burned  in  about 
one  two-hundredth  part  of  a  second  under  pressure  in  the 
barrel  of  a  gun. 


32  MOTORS    AND   MOTORING 

burnt  in  the  cylinder  in  presence  of  nitrogen,  and  some 
of  the  products  from  the  previous  explosion.  So  it  is 
usual  to  allow  about  twice  the  theoretical  quantity,  or 
30  Ibs.,  of  air  to  completely  carburate  1  Ib.  of  gasolene. 
If  space  permitted,  it  would  be  instructive  to  examine 
under  what  conditions  of  temperature,  pressure,  and 
proportions  a  combustible  gas  combines  completely  with 
oxygen,  but  as  a  matter  of  practice  in  running,  the  most 
economical  mixture  to  be  used  in  the  cylinder  of  a 
motor  is  usually  determined  by  trial  at  average  speed, 
the  carburettor  being  adjusted  to  give  the  best  results, 
without  the  exact  proportion  of  air  and  gasolene  vapor 
passing  through  it  being  known. 

22.  Horse-Power. — In  speaking  of  power,  we  must  be 
careful  to  distinguish  it  from  the  term  force,  as  the  two 
words  are  not  synonymous.  The  former  term  was  very 
loosely  used  by  the  older  writers  on  mechanics  when 
referring  to  force;  but  power,  it  should  be  understood, 
is  the  rate  of  doing  work,  that  is  to  say,  if  we  are  to 
measure  work  we  must  know  the  amount  of  work  done 

in  a  given  time,  then  the  quotient^ equals  the  power. 

The  unit  of  power  was  fixed  by  James  Watt,  who  found, 
by  experiment,  that  the  maximum  amount  of  work  a 
powerful  dray  horse  could  do  when  pulling  regularly  at 
a  slow  speed  for  eight  hours  a  day,  was  at  the  rate  of 
33,000  foot-pounds  per  minute.1  Hence  one  horse- 
power=33,000  ft.-lbs.  per  minute.2  So  to  determine 
the  horse-power  (usually  abbreviated  to  H.P.)  of  any 
motor,  we  have  simply  to  calculate  in  foot-pounds  the 
work  done  by  it  in  one  minute,  and  divide  by  33,000. 

But  we  must  decide  first  whether  we  wish  to  measure 
the  power  of  the  motor  to  do  work  outside  itself,  the 

1  It  is  well  known  that  the  ordinary  draught  horse  is  not 
capable  of  doing  more  than  about  22,000  ft.-lbs.  per  minute, 
or  about  two-thirds  of  the  standard  amount. 

2  The  French   force-de-cheval,  or  metric  horse-power=75 
kilogram-metres   per  second=542.48  ft-lbs.   per  second,   or 
QT986  the  horse-power, 


MOTOKS    AND    MOTOKING  33 

effective  power  available  to  drive  the  car  through  the 
gear,  or  do  work  in  overcoming  the  friction  of  a  clutch 
or  brake  applied  to  its  fly-wheel,  which  is  called  'brake 
horse-power  (B.H.P.) ;  J  or,  on  the  other  hand,  whether 
we  are  to  measure  the  indicated  horse-power  (I.H.P.), 
the  power  developed  in  the  cylinder  of  the  motor  by  the 
varying  pressure  of  the  expanding  gases  acting  on  the 
piston,  called  indicated,  because  an  instrument  known 
as  an  indicator  is  used  to  declare  or  indicate  the  varia- 
tions in  the  pressure  on  the  piston,  from  which  the 
mean  pressure  can  be  easily  found,  and  this,  multiplied 
by  the  distance  in  feet  per  minute  the  piston  travels  in 
doing  its  working  strokes^  and  divided  by  33,000,  gives 
the  indicated  horse-power. 

23.  The  Mechanical  Efficiency  of  the  Engine  takes 
account  of  all  the  frictional  resistances,  and  compares 
the  work  given  out  by  the  crank-shaft  with  that  done  in 
the  cylinder. 

.    .     „  .  brake  horse-power 

Thus,  mechanical  efficiency=  .— 7= — : 

indicated  horse-power, 

the  value  of  the  quotient  varies;  it  decreases  somewhat 
as  the  size  of  the  engine  becomes  very  small,  and  also 
decreases  in  any  given  engine  as  the  power  at  which  it 
is  being  worked  is  reduced  much  below  that  which  it 
was  designed  to  develop;  this  is  due  to  the  fact  that  its 
frictional  resistances  are  somewhat  less  at  full  power 
than  at  any  lower  power,  although,  of  course,  they  in- 
crease with  the  power,  but  not  quite  in  the  same  pro- 
portion. Thus  a  20  horse-power  motor  (if  well  designed 
for  that  power)  would  probably  give  17  horse-power  at 
the  brakes,  and  would  therefore  have  a  mechanical  effi- 
ciency of  17/20— -85,  or  85  per  cent.,2  but  the  same  en- 

lrThe  brake  horse-power  is  measured  by  using  a  friction 
brake  or  dynamometer.  It  is  the  power  some  makers  refer 
to  when  advertising  their  cars.  There  is  a  marked  want 
of  uniformity  in  accurately  defining  the  power. 

2  A  good  average  result.  When  working  under  favorable 
conditions,  this  efliciency  varies  from  90  to  70  per  cent.,  that 
is  to  say,  from  10  to  30  per  cent,  of  the  full  power  developed 
in  the  cylinder  (the  indicated  horse-power)  is  lost. 


34  MOTOES   AND   MOTOKING 

gine  throttled  down  to  5  horse-power  would  probably 
not  give  out  more  than  2  H.P.  at  the  brake,  and  would 
have  a  mechanical  efficiency  of  £  =0-4,  or  40  per  cent. 

This  shows  what  has  to  be  paid  for  the  luxury  of 
driving  a  car  that  is  powerful  enough  to  negotiate  hills 
at  a  high  speed,  and  is  running  at  other  times  much 
below  its  full  power. 

24.  Fuel  Efficiency  of  the  Engine.  —  We  have  re- 
marked (Article  21)  that  few  motors  running  have  a 
heat  efficiency  as  high  as  25  per  cent.  ;  probably  20  per 
cent,  is  nearer  the  mark  the  best  cars  reach  when  run- 
ning at  their  highest  efficiency.  And,  if  we  assume 
their  mechanical  efficiency  to  be  75  per  cent.,  and  take 

20        75 
the  product  of  these  quantities, 


we  get  15  per  cent,  of  all  the  energy  of  the  fuel  given 
out  in  the  form  of  work  by  the  crank-shaft. 

Now  with  this  data  before  us,  we  will  see  what  power 
should  be  developed  at  the  crank-shaft  if  we  are  using 
a  gallon  of  0-680  gasolene  per  hour  when  running.  A 
gallon  of  this  spirit  will  weigh  6-8  Ibs.,1  and  we  have 
seen  (Article  21)  that  the  heat  units  in  one  pound  of 
gasolene  2=20,748,  therefore  the  number  in  one  gallon= 
6-8X20,748=141,086-4  B.T.U.  (equal  to  141,086X778 
ft.-lbs.),  and  therefore  the  brake  horse-power 

15(141,086X778) 


100(60X33,000) 
the  horse-power  a  motor  that  is  burning  a  gallon  of 


1  The  weight  of  a  gallon  of  liquid  is  found  by  multiplying 
its  specific  gravity  by  the  weight  of  u  gallon  of  water  (or 
10  Ibs.),  so  0.080X10=06.8  Ibs.,  which  is  the  weight  of  a 
gallon  of  0.680  gasolene  at  59°  F. 

2  In  article  21  we  referred  to  gasolene  of  specific  gravity 
0.700,  but  so  long  as  the  ratio  of  H  to  C  remains  constant, 
the  theoretical  thermal  value  per  lb.  is  the  same  for  all 
densities. 

8  This  is  the  power  given  out  at  the  crank-shaft.  There 
are  further  losses  in  transmitting  it  to  the  road  wheels,  as 
we  shall  see. 


MOTORS   AND   MOTORING  35 

gasolene  an  hour  can  be  expected  to  give  out  is  an  av- 
erage of  8£,  nearly  equivalent  to — =11-08,  say, 

11  indicated  horse-power. 

As  some  cars  run  30  miles  (at  about  20  miles  per 
hour)  on  a  gallon  of  gasolene,  it  follows  that  their 
brake  horse-power  and  indicated  horse-power  can  very 
little  exceed  an  average  of  §X8-315=5-543,  and  fXll-08 
=7-386  respectively. 

Of  course  engines  fitted  with  ball  bearings  have  a 
higher  mechanical  efficiency,  and  give  out  a  propor- 
tionately higher  B.H.P. 

IGNITION 

25.  There  is  no  part  of  the  gasolene  motor  of  greater 
importance  than  the  ignition  apparatus,  the  slightest 
disarrangement  of  which  invariably  causes  trouble,  as 
every  driver  soon  discovers,  for  he  finds  that  most  stop- 
pages are  due  to  something  abnormal  occurring  to  this 
all-important  part.  Of  course,  the  function  of  the  igni- 
tion apparatus  is  to  ignite  the  charge  of  explosive  mix- 
ture in  the  cylinder  on  or  about  the  completion  of  the 
compression  stroke,  when  the  charge  is  at  the  maximum 
pressure  due  to  compression,  and  a  working  stroke  is 
about  to  commence.     This  ignition  was  formerly  very 
generally  effected  by  what  is  called — 

26.  Tube  Ignition. — A  small  platinum  tube,  closed 
at  one  end,  being  fitted  to  the  cylinder  in  the  combus- 
tion chamber,  the  closed  end  projecting  outside,  and 
heated  to  incandescence  by  a  blow-lamp  of  the  Bunsen 
burner  type1  fed  from  the  gasolene-tank,  the  mixture 
being  forced  into  the  tube  and  ignited  each  time  com- 
pression occurred.     It  might  be  supposed  that  with  this 

1  There  was  some  difficulty  in  keeping  the  lamp  alight 
when  the  wind  caught  the  car  in  certain  directions,  and 
the  flame  was  apt  to  get  deflected  from  the  ignition  tube, 
allowing  it  to  cool  down  enough  to  cause  late  firing,  with 
weaker  explosion,  and  consequent  loss  of  power. 


36  MOTOES    AND   MOTOKING 

arrangement  the  charge  would  be  apt  to  ignite  before 
the  completion  of  the  compression  stroke  (indeed,  this 
pre-ignition  does  sometimes  occur,  accompanied  by  a 
peculiar  sound,  which  if  once  heard  is  easily  recognized), 
retarding  the  piston  as  it  nears  the  end  of  its  stroke, 
and  putting  a  severe  strain  upon  all  the  bearings;  but 
by  moving  the  lamp  to  another  part  of  the  tube,  farther 
away  from  the  cylinder,  the  time  of  firing  can  be  re- 
tarded,1 and  this  retardation  made  to  vary  the  power 
and  speed  of  the  engine.  Thus  the  singular  synchron- 
ism of  pressure  and  ignition,  due  to  the  mixture  be- 
coming rapidly  more  explosive  as  its  pressure  increases, 
is  capable  of  being  adjusted.  Of  course,  should  the 
valves  be  leaky,  the  compression  suffers,  and  the  mix- 
ture is  not  forced  to  the  part  of  the  tube  directly  over 
the  flame  (which  would  be  more  or  less  filled  with  the 
burnt  gases  from  the  previous  stroke),  the  timing  or 
moment  of  ignition  being  affected  with  constant  reduc- 
tion in  power.  Again,  with  this  arrangement,  if  the 
lamp  be  adjusted  for  a  certain  speed,  it  is  not  right  for 
a  higher  or  lower  one,  but  the  arrangement  has  been 
made  to  give  very  good  results  on  comparatively  slow- 
running  engines,  with  a  limited  range  of  speed.  But 
the  principal  reason  why  tube  ignition  has  practically 
died  out  is,  the  time  of  firing  the  charge  was  not  vari- 
able at  the  hands  of  the  driver.  However,  notwith- 
standing these  disadvantages,  a  few  cars  are  still  so 
fitted  as  a  reserve  or  stand-by,  in  case  the  electric  igni- 
tion should  fail,  but  even  for  this  purpose  it  is  doubtful 
if  it  will  much  longer  survive,  owing  to  the  danger  of 
using  a  naked  light  on  the  car.  To  the  use  of  an  elec- 
tric spark  to  ignite  the  explosive  mixture  in  gasolene 
engines  at  a  moment  which  can  be  controlled  by  the 
driver,  giving  him  command  over  a  wide  range  of 
speed,  not  a  little  of  the  wonderful  development  of  the 
motor  is  due,  and  we  must  now  give  some  attention  to — 


1  Another  arrangement  used  to  advance  and  retard  the 
ignition  is  a  nipple  whose  orifice  can  be  regulated. 


MOTORS   AND   MOTORING  37 

27.  Electric  Ignition,  which  is  a  great  advance  over 
the  method  just  described,  as,  with  it,  greater  compres- 
sion is  possible  and  there  is  absolute  immunity  against 
fire.  Needless  to  say,  the  object  of  the  electric  ignition 
apparatus  is  to  produce  automatically  a  very  hot  electric 
spark  (as  blue  as  possible)  in  the  midst  of  the  explosive 
mixture,  at  or  about  the  moment  the  working  stroke 
commences.  There  are  two  systems  at  present  in  use — 
(a)  the  well-known  high-tension  ignition,  involving  the 
use  of  induction  coils,  with  either  accumulators  or  bat- 
teries, and  (&)  electro-magnetic  ignition. 

In  the  former  the  electric  current  is  produced  by 
what  we  may  call  chemical  means,  whilst  in  the  latter 
system  small  dynamos  or  magnetos,  driven  by  the  motor 
itself,  mechanically  generate  the  current  used  for  firing 
the  mixture,  but  as  they  only  work  when  the  motor  is 
running,  the  electric  current  required  to  start  the  en- 
gine has  to  be  generated  either  by  giving  a  certain  speed 
to  the  engine,  by  working  the  starting  handle,  or  the 
current  for  starting  is  supplied  by  an  accumulator, 
which,  when  necessary,  is  recharged  by  the  dynamo. 
On  the  other  hand,  these  machines  have  many  advan- 
tages, not  the  least  important  of  which  is  freedom  from 
stoppages  due  to  short  circuits  and  leakage;  they  also 
can  be  made  to  give  a  hotter  spark  than  primary  bat- 
teries and  accumulators  and  are  therefore  more  capable 
of  causing  complete  ignition  of  a  big  charge,  but,  as  at 
present  made,  their  delicate  construction  makes  them 
liable  to  give  a  deal  of  trouble.  However,  there  are 
several  types  striving  for  supremacy,1  and  it  is  not 
possible  to  predict  the  ultimate  issue;  so,  many  makers 
and  motorists  are  awaiting  developments  before  making 
any  change  in  their  ignition  arrangements. 

Although  the  balance  is  in  favor  of  the  final  form 
being  of  the  electro-magnetic  type,  the  high-tension  igni- 
tion system,  with  accumulators  and  induction  coils,  pre- 

1  There  is  sure  to  be  some  marked  improvements  and 
interesting  developments  in  this  direction  before  long. 


38  MOTORS    AXD   MOTORING 

viously  referred  to,  still  holds  its  own,  owing  to  its  sim- 
plicity and  reliability,  and,  therefore,  may  be  briefly 
examined,  but  the  exigencies  of  space  forbid  the  author 
doing  anything  like  justice  to  it.  Referring  to  Fig.  1, 
it  will  be  seen  that  this  electrical  system  consists  of  (1) 
the  accumulator  or  battery,  (2)  the  coil,  (3)  the  com- 
mutator or  contact  maker  and  breaker,  (4)  the  spark- 
ing plug,  (5)  the  switch;  and  we  may  now  proceed  to 
describe  these  parts  before  attempting  to  explain  how 
they  must  be  linked  up  to  form  a  complete  system;  so 
we  may  commence  with — 

28.  The  Battery,  or  Accumulator. — This  is  called  a 
primary  battery  if  it  is  so  arranged  that  electricity  is 
created  by  the  chemical  action  of  acid  solution  upon 
zinc  and  carbon  plates,  but  if  it  consists  of  a  series  of 
lead  grids  or  plates,  some  filled  with  a  paste  of  peroxide 
of  lead,  forming  the  positive  element,  and  others  filled 
with  pure  lead  in  a  finely  divided  or  spongy  condition 
forming  the  negative  element,  placed  in  a  liquid-proof 
receptacle  filled  with  water  acidulated  with  sulphuric 
acid,  it  is  an  accumulator  (or  secondary  or  storage  bat- 
tery), which  can  accumulate  or  store1  within  itself  a 
charge  of  electricity  from  a  dynamo,  or  a  primary  bat- 
tery of  suitable  construction.  When  discharged,  both 

1  Strictly  speaking,  it  does  not  actually  store  electricity. 
The  lead  plates  and  lead-peroxide,  by  means  of  a  continuous 
current  or  charge  from  some  outside  source,  are  so  changed 
that  they  become  capable,  owing  to  their  chemical  condi- 
tion, of  themselves  creating  a  flow  of  electricity  when  the 
circuit  is  closed.  The  usual  cells  are  of  two  distinct  types 
— namely,  the  Plante,  in  which  the  active  material  is  chem- 
ically or  electrically  formed  out  of  the  surface  of  the  leaden 
conductor,  and  the  Faure,  in  which  the  active  material  is 
formed  into  a  paste,  and  is  caused  to  adhere  to  a  lead  grid 
or  conductor.  The  former  type  is  superior  for  durability, 
but  the  latter  has  the  great  advantage  of  being  much  less 
expensive  in  manufacture.  Most  of  the  accumulators  now 
made  are  one  or  the  other  of  these  types,  only  differing  in 
constructional  details.  They  all  have  a  very  low  internal 
resistance  compared  with  any  form  of  primary  battery. 
Some  automobile  makers  now  use  accumulators  fitted  with 
Plante  positive  plates  and  Faure  negatives  for  traction. 


MOTORS    AND   MOTORING  39 

the  positive,  or  lead-peroxide  plates,  and  the  negative, 
or  spongy  lead  plates,  are  largely  converted  into  lead 
sulphate.  When  being  charged,  the  lead  sulphate  un- 
dergoes a  chemical  change,  due  to  the  electrolytic  action 
of  the  charging  current,  which  converts  the  positive 
plates  once  more  into  peroxide  of  lead,  and  the  negative 
plates  into  spongy  metallic  lead.  These  two  elements 
in  the  sulphuric  acid  solution  give  an  electro-motive 
force  of  about  2-2  volts.  Thus  the  accumulator  creates 
electrical  energy  in  the  same  sense  as  a  primary  battery 
does,  i.e.,  by  chemical  action,  but  is  renewable,  when 
exhausted,  by  passing  through  it  a  current  of  electricity 
from  another  source,  in  the  opposite  direction  to  that 
taken  from  it  in  discharging.1 

Accumulators  are  more  generally  used  than  primary 
batteries,  for  although  they  have  not  the  same  capacity 
(will  not  be  efficient  for  so  many  miles)  bulk  for  bulk, 
when  properly  used  they  have  not  to  be  replaced  by  new 
ones  after  they  have  become  exhausted,  as  must  be 
done  with  the  latter.2  As  in  both  cases  the  method  of 
using  them  and  their  function  is  the  same,  either  can 
be  used  in  this  system  of  ignition,  but  for  the  reasons 
given  we  will  assume  that  accumulators  are  preferred. 
Now,  each  accumulator  is  fitted  with  two  terminals, 
called  positive  and  negative  poles,  arranged  so  that 

1The  life  of  the  accumulator  greatly  depends  upon  the 
care  taken  in  charging  and  discharging,  and  upon  the  purity 
of  the  materials  used,  and  it  is  false  economy  to  buy  anything 
but  the  best  cells. 

2  Primary  batteries  are  usually  dry  ones,  modifications 
of  the  simple  voltaic  elements,  zinc  and  carbon,  of  constant 
or  non-polarlzable  type,  filled  with  some  material  to  prevent 
the  liquid  electrolyte  from  spilling.  A  battery  usually  con- 
sists of  four  cells,  and  although  the  initial  cost  of  these  is 
far  less  than  that  of  accumulators,  and  they  are  capable  of 
standing  rougher  and  more  irregular  treatment,  they  are 
not  so  economical,  as  their  energy  depends  upon  the  con- 
sumption of  the  zinc  plates,  and  when  these  have  been  used 
up,  the  cells  are  practically  worthless,  and  must  be  replaced. 
So,  for  continual  use,  this  makes  them  ultimately  twice  as 
costly  as  accumulators. 


40  MOTORS   AND   MOTORING 

wires  can  be  connected  to  them  by  means  of  set  screws. 
If  these  terminals  be  connected  by  a  wire  (completing 
the  circuit),  electricity  will  flow  from  the  positive  to 
the  negative  terminal  continuously,  and  in  so  doing 
will  gradually  discharge  the  accumulator.  Electricity 
flows  with  very  little  resistance  through  all  metallic 
substances,  and  with  more  resistance  through  water  or 
across  any  moist  or  wet  surface.  If  a  wire  carrying  a 
current  comes  into  contact  with  any  metallic  substance 
in  more  than  one  place,  the  current  will  divide  between 
the  two;  in  this  case  the  wire  is  said  to  be  short-cir- 
cuited at  that  part.  Therefore,  in  conveying  current 
from  one  part  of  the  motor  to  another  x  the  wires  must 
be  (insulated)  covered  with  insulating  materials,  those 
of  an  india-rubber  nature  being  found  most  efficient. 
The  higher  the  tension  or  pressure  used  to  urge  the 
current  through  the  circuit,  the  thicker  must  the  non- 
conducting cover  be,  for  if  the  insulation  be  not  suffi- 
ciently good,  electricity  may  leak  through  the  engine 
frame  to  the  negative  pole  (become  short-circuited,  or 
shorted,  as  it  is  sometimes  called).  Now,  the  electrical 
current,  as  it  is  discharged  from  the  accumulator,  is  not 
lacking  in  quantity  (amperage),2  but  it  is  of  too  low 
voltage  3  or  pressure,  and  to  get  a  current  to  pass,  in 
the  form  of  sparks,  across  the  small  insulating  gap  at 
the  end  of  the  sparking  plug,  the  pressure  must  be 

*To  reduce  the  resistance  to  a  minimum,  and  avoid  the 
chance  of  leakage,  these  connections  should  be  as  direct 
and  short  as  possible,  and  great  care  should  be  taken  in 
making  them. 

2  The  ampere  is  the  unit  of  current,  or  the  unit  rate  of 
flow  of  electricity ;  and  the  ampere-hour  equals  the  ampere 
flowing  for  one  hour. 

3  The  volt  is   the  unit  of  pressure,  electro-motive  force 
(B.M.F.),    or    potential    difference    (P.D.).     The    unit    of 
resistance  which  the  conductor  offers  to  the  flow  of  current 
through  it  is  the  Ohm,  and  E.M.F.=AmperesXOhrns. 

The  watt  equals  the  ampere  multiplied  by  the  volt,  and 
the  watt-hour  equals  the  energy  expended  in  one  hour  by 
one  watt,  which  equals  3600  joules,  or  3600  X. 7373=2654.28 
foot-pounds. 


MOTORS   AND   MOTORING  41 

raised  from  that  of  the  accumulator  cells,  viz.,  about 
4-4  volts,  to  some  thousands  of  volts;  so,  to  transform 
it  into  the  high-tension  current  necessary  for  this  pur- 
pose, it  is  passed  through  an — 

29.  Induction  Coil. — When  the  current  flows  from 
the  accumulator,  it  is  conducted  through  several  turns 
of  insulated  wire  (about  20  gauge),  wound  round  a 
central  core  of  soft  iron  wire.  This  is  known  as  the 
"primary"  or  "low-tension"  winding.  From  there 
it  passes  to  a  contact-breaker,  which  automatically 
opens  and  closes  the  circuit,  and  then  flows  back  to  the 
accumulator,  so  completing  the  circuit.  Round  this 
primary  coil  (but  well  insulated  from  it)  is  wound  a 
second  coil  of  very  many  turns  of  fine  wire  (about  32 
gauge),  the  ends  of  which  are  connected  to  the  termi- 
nals of  the  sparking  plug.  This  coil  is  known  as  the 
"  secondary  "  or  "  high-tension  "  winding.  When  the 
primary  current  flows,  it  magnetizes  the  iron  core  and 
the  magnetic  field  established  interlinks  with  the  very 
many  turns  of  the  secondary  coil;  it  also  immediately 
attracts  the  iron  armature  of  the  contact-breaker,  and 
so  breaks  the  circuit.  The  magnetic  field  then  disap- 
pears, and  the  spring  of  the  contact-breaker  pulls  the 
armature  back  to  its  original  position.  This  again  com- 
pletes the  circuit,  and  the  magnetic  field  once  more 
interlinks  with  the  secondary  coil,  and  the  whole  opera- 
tion is  repeated  in  this  way  several  times  a  second. 

The  magnetic  field,  in  surging  through  the  secondary 
coil  of  many  turns,  induces  in  it  an  electrical  pressure 
high  enough  to  break  down  the  insulating  gap  at  the 
sparking  plug  points,  resulting  in  a  discharge  across  it 
in  the  form  of  sparks,  which  ignites  the  explosive  mix- 
ture in  the  cylinder.  The  power  and  efficiency  of  the 
coil  is  greatly  increased  by  being  fitted  with  a  condenser, 
made  up  of  a  series  of  alternate  layers  of  fine  tinfoil 
and  paraffined-waxed  paper,  the  connections  being  so 
made  that  when  the  current  through  the  primary  wind- 
ing is  interrupted  by  the  vibration  of  the  trembler,  the 
condenser  acts  as  a  "  shunt  circuit,"  and  stores  up  en- 


42  MOTORS   AND   MOTORING 

ergy  which  would  otherwise  dissipate  itself  in  a  very 
destructive  spark  at  the  platinum  contacts  of  the  cir- 
cuit-breaker/ and  this  stored-up  energy  helps  the  cur- 
rent to  rise  quickly  in  the  primary  coils  at  the  next 
making  of  the  circuit.  The  efficiency  of  the  spark  de- 
pends on  the  large  number  of  turns  in  the  secondary 
winding  as  compared  with  the  primary  turns,  also  on 
the  rapidity  with  which  the  primary  circuit  is  broken, 
and  on  the  strong  magnetic  field  of  the  soft  iron  core 
when  temporarily  turned  into  a  powerful  magnet. 
Another  important  detail  of  the  system  is  the — 

30.  Contact-Breaker,  or  Commutator.2 — This  is  gen- 
erally of  the  wiping  contact  type  3  as  shown  in  Fig.  1, 
and  consists  of  an  insulated  disc  (usually  made  of  fiber) 
fixed  to  the  half-speed  shaft.    At  a  fixed  point  on  this 
disc  is  a  sector  of  brass  connected  directly  to  the  shaft, 
which  again  is  in  metallic  contact  with  the  frame  of  the 
motor. 

A  metal  brush  or  collector,  insulated  from  the  frame 
of  the  engine,  and  in  metallic  contact  with  one  terminal 
of  the  primary  coil,  ordinarily  rests  on  the  insulated 
disc,  and  we  shall  explain  directly  what  part  this  com- 
mutator plays  in  the  complete  system. 

31.  The  Sparking  Plug. — The  principal  features  of 
the  sparking  plug  or  igniter  are  shown  in  Fig.  11,  which 

1  If  an  inefficient  condenser  be  fitted    a  strong  spark  is 
obtained   when    the   circuit   between    the   platinum-pointed 
screw  and  trembler  is  broken,  which  quickly  causes  unsat- 
isfactory working  by  burning  away  the  contacts,   necessi- 
tating readjustments  and  wasting  current. 

2  The  two  terms  contact-breaker  and  commutator  are  not 
synonymous,  therefore  they  must  be  correctly  used.     A  con- 
tact-breaker is  fitted  to  a  single-cylinder  engine,  and  a  com- 
mutator  to    a   multi-cylinder   one,    though    in    both    cases, 
types  and  designs  may  be  precisely  similar.     In  the  latter 
case  its  function  is  to  commute  the  current  from  one  path 
to  another,  or,  more  explicitly,  from  one  cylinder  to  another. 
In  the  well-known  apparatus  introduced  by  Mr.  F.  C.  Blake 
of  Kew,  two  or  more  cylinders  are  fired  by  means  of  a 
single  coil  with  a  high-speed  trembler. 

"The  other  type,  which  was  formerly  so  much  used,  is 
the  spring-blade  or  trembler  contact-breaker. 


MOTORS   AND   MOTORING  43 

represents  the  De  Dion  Bouton  new  pattern  plug.  Into 
a  brass  or  gun-metal  shell  S  (which  is  screwed  into  a 
cylinder  wall,  and  is  in  metallic  contact  with  it)  a  hol- 
low non-conducting  plug  D,  made  of  porcelain  (or  com- 
pressed mica),  is  held  in  position  by  the  gland  nut  N, 
and  through  plug  D  a  wire  is  fixed,  the  pointed  end  P 
being  of  platinum,  and  the  other  end  E  being  in  me- 
tallic contact  with  the  brass  cap  C,  on  to  which  the 
insulated  copper  wire  from  the  induction  coil,  carrying 
the  high-tension  current,  is  screwed  by  the  brass  fly- 
nut  P,  placing  the  platinum  point  P  in  metallic  con- 
tact with  the  wire  from  the  coil.  The  other  platinum 
point  Q  is  fixed  in  the  brass  shell  S,  so  that  PQ  forms 


SPARKING  PLUG. 
WATER  SPACE 


BRASS 


Fig.  11. 

the  spark  gap,  and  we  shall  explain  directly  what  occurs 
when  the  plug  is  in  use. 

32.  External  Plug  Gap. — By  introducing  a  second 
gap  into  the  high-tension  circuit,  a  spark  can  be  main- 
tained inside  the  cylinder  under  conditions  which 
would  otherwise  prevent  any  effective  ignition  taking 
place,  and  contrivances  have  been  introduced  for  at- 
taching to  the  sparking  plug,  so  that  external  sparks 


44  MOTORS   AND   MOTORING 

can  be  obtained.  This  not  only  intensifies  the  spark, 
but  assists  in  preventing  trouble  due  to  sooting  of  the 
plug,  and  enables  the  driver  to  see  at  a  glance  whether 
current  is  passing  through  each  of  the  plugs;  and 
another  advantage  is,  he  has  not  to  resort  to  the  com- 
mon but  clumsy  method  of  discovering  an  erring  plug 
by  opening  the  coil  box  and  holding  down  the  trembler, 
so  that  one  cylinder  is  left  in  at  a  time.  These  plugs 
appear  to  be  dropping  out  of  favor. 

33.  The  Switch  is  a  simple  contrivance  by  means  of 
which  the  primary  circuit  can  easily  be  made  or  broken 
by  a  small  movement  of  the  metal  connecting  piece. 
The  switch  is  used  for  momentary  breaks  in  running 
the  engine ;  by  its  use  the  current  from  the  accumulator 
is  switched  on  or  off  the  induction  coil.     Of  course  the 
switch  is  used  to  break  or  make  the  circuit  when  the 
engine  is  stopped  or  started.    There  are  several  types  of 
switch,  the  latest  and  most  convenient  for  motor  cycles 
being  that  operated  by  the  preliminary  movement  of 
applying  the  brake. 

34.  An  Interrupter  is  merely  a  means  of  conveniently 
breaking  the  circuit  when  the  motor  is  not  to  be  used 
for  a  considerable  period.    Motor  bicycles  are  generally 
fitted  with  a  plug  interrupter,  which  can  be  carried  in 
the  cyclist's  pocket  when  the  machine  is  not  being  used. 

35.  The  Complete  Ignition  System. — We  may  now 
summarize  the  various  parts  which,  connected  together, 
form  the  complete  system.    Commencing  with  the  accu- 
mulator, Fig.  1,  we  have  one  of  its  poles  connected  with 
one  end  of  the  primary  coil  of  the  induction  coil,  the 
other  end  being  connected  (through  the  switch)  to  the 
brush  of  the  contact-breaker,  so  that  the  low-tension 
current  can  pass  through  the  disc  to  the  engine  frame 
and  from  the  frame  to  the  accumulator  again,  through 
the  connecting  wire    (called  earth  wire).     When    the 
switch  is  on  and  the  motor  revolving,  the  half-speed 
shaft  turns  until  the  metal  segment  N  touches  the  brush 
or  collector  0 ;  this  completes  the  circuit,  and  the  cur- 
rent passes  through  the  primary  coil,  agitates  the  trem- 


MOTORS   AND   MOTORING  45 

bier,  and  the  high-tension  current  is  induced  to  the  sec- 
ondary coil.  This  high-tension  or  secondary  current 
passes  directly  to  the  insulated  portion  of  the  sparking 
plug  (as  shown,  Fig.  11),  and  being,  as  it  were,  im- 
prisoned on  all  sides  by  insulated  material  through 
which  it  cannot  escape,  jumps  across  the  space  between 
the  platinum  points,  in  the  path  of  least  resistance,  and 
in  so  doing  produces  at  the  right  moment  a  stream  of 
intensely  hot  sparks  in  the  gap  between  the  sparking 
plug  points,  igniting  the  explosive  mixture  surround- 
ing it.  The  high-tension  circuit  being  completed 
through  the  engine  frame  and  earth  wire  to  induction 
coil. 

36.  Accumulators,  Charging,  etc. — The  accumulator 
used  for  our  purpose l  usually  consists  of  two  cells,  each 
with  a  voltage  of  2-2,  and  being  connected  in  series,2 
as  they  always  are  for  this  ignition  apparatus,  the 
result  is  a  working  voltage  of  2X2-2  =  4-4,  but  when 
the  cells  are  fully  charged,  it  may  almost  reach  5  volts. 
There  are  several  methods  of  charging  accumulators, 
but  we  need  only  mention  the  following  three.  First — 
Charging  from  primary  batteries. — This  is  a  method 
that  is  within  the  reach  of  every  motorist  who  is  not 
afraid  of  a  little  trouble.  The  first  cost  of  a  good  four- 
cell  primary  battery  does  not  amount  to  much,  and  the 
same  remark  applies  to  the  cost  of  charging,  if  all  the 
materials  are  used  up  before  they  are  replaced.  If 
the  motorist  has  only  a  very  limited  knowledge  of 
electricity,  he  would  be  wise  to  get  an  electrician  to 
arrange  everything  for  him  at  first  and  this  advice  also 
applies  to  the  other  two  methods  to  be  explained ;  indeed, 
many  car-owners  prefer  to  send  their  accumulators  to 
the  makers,  or  to  an  agent  who  undertakes  the  work, 
to  be  recharged,  rather  than  be  bothered  or  run  any 

Accumulators  are  used  for  lighting,  as  well  as  for  igni- 
tion and  traction. 

2  In  series,  the  positive  or  peroxide  pole  of  one  cell  (usu- 
ally painted  red)  is  connected  to  the  negative  or  spongy 
lead  plate  of  the  next  cell. 


46  MOTOKS    AND   MOTOKING 

risk  of  making  mistakes;  but  they  should  make  an 
effort  to  understand  these  things  to  protect  themselves, 
and  to  be  able  to  put  things  right  in  case  of  emergency. 
The  second  method  is  by  charging  from  electric  mains, 
using  lamps  solely  as  a  resistance:  this  is  by  far  the 
most  popular,  but  unless  several  cells  can  be  charged 
at  the  same  time,  it  is  the  most  extravagant.  The  third 
method,  which  is  by  far  the  best  when  practicable,  is 
to  charge  from  electric  mains,  using,  as  a  resistance, 
lamps  which  would  in  any  case  be  used  for  lighting 
purposes.  It  entails  a  small  outlay  for  slightly  altering 
the  wiring  of  the  room  to  be  used,  but  should  the  car- 
owner  have  the  electric  light  in  his  coach-house,  it  can 
be  easily  arranged  for  the  purpose,  and  the  accumula- 
tors can  then  be  charged  when  the  lights  are  used  for 
ordinary  purposes,  the  only  noticeable  effect  of  this 
being  a  slight  decrease  in  the  intensity  of  the  light; 
the  current  then  practically  costs  nothing.  An  addi- 
tional advantage  due  to  this  way  of  charging  is  that 
accumulators  can  be  kept  nearly  always  fully  charged. 
Indeed,  they  should  be  charged  whenever  possible,  to 
keep  them  in  order.  Of  course,  it  must  be  direct  cur- 
rent electricity,  as  an  alternating  current  would  charge 
and  discharge  with  each  alternation.  Now,  to  keep  the 
cells  in  order,  it  is  best  not  to  withdraw  more  than 
about  25  per  cent,  of  the  total  charge  from  them  before 
recharging;  but  much  more,  say  up  to  70  or  75  per 
cent.,  can  be  discharged  if  the  cells  are  recharged 
immediately.  They  should  always  be  fully  charged 
before  being  put  out  of  action  for  any  considerable  time, 
as  there  is  a  constant  tendency  for  an  automatic  dis- 
charge to  occur.  The  normal  discharge  rate  through 
a  coil  of  good  construction  is  about  half  an  ampere, 
so  that  if  the  accumulator  cells  have  a  capacity,  as 
many  of  them  have,  of  40  ampere-hours/  and  the  read- 

lrThe  quantity  of  electricity  flowing  into  or  out  of  an 
accumulator  is  computed  in  ampere-hours,  and  the  rate  at 
which  it  passes  a  given  point  in  the  circuit  is  indicated  in 
amperes. 


MOTOBS   AND   MOTOEING  47 

ing  of  the  ammeter  *  is  half  an  ampere,  and  about  50 
per  cent,  of  the  total  charge  be  withdrawn,  it  can  be 
used  for  about  40  hours;  but  suppose  the  commutator 
only  makes  contact  for  one-fourth  of  a  revolution,  the 
accumulator  is  only  giving  current  for  one-fourth  of  the 
time,  then  it  can  be  run  for  4  X  40,  or  160  working 
hours. 

All  accumulators  are  constructed  to  charge  and  dis- 
charge at  a  certain  rate,  and  any  attempt  to  force  the 
rate  of  either  charging  or  discharging  inevitably  results 
in  the  peroxide  paste  being  forced  out  of  the  grids, 
and  the  latter  being  bent  and  buckled  by  the  stress. 
This  often  occurs  due  to  shorting,  when  the  terminals 
are  connected  by  a  good  conductor  to  ascertain  what 
charge,  if  any,  remains  in  the  accumulator.  Of  course 
this  should  never  be  done  without  a  resistance,  such 
as  the  coil,  in  circuit,  nor  should  the  ampere-meter  be 
connected  direct  across  the  terminals,  as  in  either  case 
it  would  allow  the  accumulator  to  discharge  at  many 
times  its  correct  rate.  On  the  other  hand,  a  volt-meter  2 
may  be  connected  in  this  way  to  take  the  reading,  as 
it  has  a  high  resistance,  and  takes  but  an  infinitesimal 
current. 

This  brings  us  to  the  question  of  measuring  the 
charge  in  the  accumulator. 

37.  The  Voltage  of  the  Current. — Let  us  assume  that 
we  have  before  us  an  accumulator  consisting  of  the 
usual  two  cells  fully  charged,  each  to  a  voltage  of  2-2, 
giving  a  voltage  of  4-4  when  connected  in  series  and 
tested  with  the  volt-meter.  We  may  also  assume  that 
on  being  tested  with  an  ammeter 3  (connected  up  to 

1  The  ammeter,   or  ampere-meter,   is  an  instrument  for 
indicating  the  rate  of  charge  or  discharge  in  amperes. 

2  An  instrument  for  indicating  the  electro-motive-force,  or 
the  electrical  pressure  in  a  circuit,  or  at  the  terminals  of  a 
battery  or  dynamo. 

8  In  testing  dry  batteries  for  capacity,  an  ammeter  should 
be  used,  not  a  voltmeter,  because  the  voltage  indicated  when 
the  battery  is  nearly  run  out  is  almost  the  same  as  when 
new;  the  resistance  of  the  battery  and  voltmeter  together 


48  MOTORS    AND    MOTORING 

the  coil  whilst  working  and  included  in  series  connec- 
tion 1)  its  discharge  rate  is  found  to  be  half  an  ampere, 
and  that  the  charge  is  30  ampere-hours,2  we  should 
find  that  as  the  current  is  discharged  there  is  a  gradual 
fall  in  the  voltage,  until,  when  about  half  has  been 
withdrawn,  the  voltage  would  be  only  about  4,  and  if 
the  withdrawal  of  current  be  continued,  the  fall  in 
voltage  becomes  far  more  rapid  till  it  drops  to  3-6, 
at  which  reading  the  accumulator  is  considered  to  be 
exhausted  or  discharged. 

38.  Spare  Accumulators. — It  is  usual  to  carry  a  spare 
set  of  accumulators,  and  these  are  often  connected  up 
by  a  two-way  switch,  so  that  they  can  be  put  in  circuit 
and   the   others   disconnected   at   any  moment.      This 
arrangement  takes  up  no  more  room  than  the  four-cell 
primary  battery  it  often  replaces. 

39.  testing  on  a  Closed  Circuit. — The  expedient  of 
using  a  small  incandescent  lamp  of  the  same  voltage  as 
the  accumulator  is  a  good  one.    This  is  connected  across 
the  terminals  for  a  moment  or  two,  and  if  it  lights  up 
brightly  and  the  light    is    sustained,  then   there   is    a 
charge  in  the  accumulator,  but  if  it  becomes  dim,  then 

to  the  passage  of  a  current  being  relatively  high,  whether 
the  battery  be  nearly  exhausted  or  almost  new.  On  the 
other  hand,  an  ammeter  offers  small  resistance,  and,  if  used 
just  long  enough  to  obtain  a  reading,  will  indicate  by  the 
quantity  of  current  passing  through  it  the  condition  of  the 
battery;  for  as  the  battery  becomes  exhausted  its  resist- 
ance increases,  and  its  capacity  for  giving  out  current 
becomes  reduced. 

iThe  internal  resistance  of  the  accumulator  being  very 
low,  unless  a  resistance,  such  as  a  coil,  be  placed  in  the 
circuit,  both  the  ammeter  and  the  accumulator  would  be 
damaged,  the  latter  being  quickly  run  down,  and  the  wind- 
ing of  the  former  seriously  over-heated. 

2  The  amount  of  electric  energy  given  out  by  an  accumu- 
lator is  always  less  than  the  amount  put  in ;  and  the  former, 
compared  with  the  latter,  represents  the  efficiency,  which 
varies  from  70  to  80  per  cent.,  according  to  the  age  of  the 
accumulator  and  the  rate  of  charging,  being  highest  when 
new  and  slowly  charged. 


MOTOES    AND   MOTORING  49 

the  accumulator  is  exhausted.  This  test  should  always 
be  made  at  the  conclusion  of  a  run,  as  the  accumulator 
is  capable  of  recovering  sufficiently  while  standing  to 
give  a  fairly  bright  light  for  a  few  moments,  even 
when  almost  exhausted.  As  this  is  a  test  of  current 
and  voltage,  it  is  very  reliable,  for  a  reading  with  a 
volt-meter  (testing  an  open  circuit}  will  sometimes  be 
almost  normal,  and  a  fall  of  voltage  occur  as  soon  as 
current  is  withdrawn. 

GOVERNING  AND   CONTROLLING 

40.  One  of  the  most  difficult  problems  the  designer 
of  a  gasolene  engine  has  to  deal  with  is  the  governing  of 
its  power  and  speed.  He  is  called  upon  to  arrange  its 
mechanism  in  such  a  way  that  the  engine  automatically 
prevents  the  production  of  more  power  in  itself  than 
is  actually  needed  for  the  propulsion  of  the  car  at  any 
particular  speed.  To  give  practical  effect  to  this  con- 
dition, designers  have  exercised  their  ingenuity  in  a 
variety  of  ways,  but  they  have  a  more  difficult  task  to 
deal  with  in  the  gasolene  engine  than  in  either  the  steam 
engine  or  ordinary  gas  engine,  as  we  shall  see  directly. 
It  is  easy  to  make  arrangements  to  enable  the  driver  to 
control'1  the  engine;  and  as  these  arrangements  have 
much  in  common  with  those  employed  in  governing, 
we  may  proceed  to  explain  that  the  amount  of  useful 
work  done  by  a  gasolene  engine  during  a  cycle  can  be 
varied  in  several  ways,  the  following  being  the  best 
known. 

(1)  Advancing    and    retarding    the    ignition,    the 

charge  being  constant. 

(2)  Advancing  and  retarding  ignition  with  fluctu- 

ating charge. 

(3)  Varying  the  amount  of  charge  by  throttling,  the 

proportion  of  the  mixture  being  constant. 

1  The  function  of  governing  differs  from  that  of  control- 
ling ;  the  engine  is  governed  automatically,  but  controlled 
by  hand, 


50  MOTOES   AND   MOTOKING 

(4)  By  throttling  the  exhaust. 

In  order  to  grasp  the  general  principles  that  underlie 
the  working  of  the  first  and  second  methods,  the  reader 
must  make  himself  familiar  with  the  effect  of — 

41.  Advancing  and  Retarding  Ignition. — The  power 
of  the  engine  can  he  varied  between  fairly  wide  limits 
by  varying  the  time  of  ignition.  If  ignition  is  to  occur 
at  the  beginning  of  a  working  stroke  for  running  the 
engine  at  its  full  power,  the  brush  of  the  commutator 
(Figs.  1  and  16)  should  commence  to  come  into  con- 
tact with  the  metallic  connecting  plate  on  the  insulated 
disc  slightly  before  the  piston  has  completed  its  com- 
pression stroke;  as  although,  theoretically,  sparking 
should  occur  at  the  instant  the  circuit  is  completed,  an 
appreciable  interval  intervenes  between  ignition  and 
the  completion  of  the  circuit.  This  is  partly  due  to  the 
number  of  points  through  which  the  current  passes, 
some  of  which  may  not  be  very  perfect,  and  to  the  fact 
that  there  is  always  an  interval  of  time  between  spark- 
ing and  actual  ignition,  the  time  required  to  ignite  the 
mixture  depending  upon  the  proportion  of  air  to  spirit 
vapor  forming  it,  upon  the  amount  of  compression,  and 
also  upon  the  proportion  of  the  exhaust  gases  mingling 
with  the  explosive  mixture.  The  interval  being  shortest 
when  the  mixture  is  perfect  and  at  maximum  com- 
pression, and  increasing  as  the  mixture  becomes 
throttled  with  a  smaller  quantity  entering  the  cylinder, 
which  in  mixing  with  the  normal  quantity  of  exhaust 
gases  in  the  clearance  or  combustion  space,  results  in 
an  impoverished  mixture  at  a  lower  compression,1  and 
a  later  ignition.  This  being  the  case,  the  expedient  of 
causing  sparking  to  occur  a  little  earlier,  that  is,  by 

lrrhe  more  the  mixture  is  throttled,  the  smaller  is  the 
volume  which  is  compressed  in  the  cylinder,  and  the  lower 
the  pressure  due  to  compression.  Thus,  if  the  cylinder  is 
fully  charged  at  atmospheric  pressure,  the  charge  be  com- 
pressed to  one-fourth  the  initial  volume,  then  at  greatest 
compression,  neglecting  refinements,  the  resulting  pressure 
would  be  4  times  atmospheric  pressure,  or,  say  4X15=60; 


MOTOES   AND   MOTOKING  51 

advancing  the  spark,  is  one  that  would  suggest  itself; 
indeed,  it  is  the  one  that  is  generally  employed,  although 
in  most  cases  in  a  somewhat  casual  way.  The  object 
should  be  to  so  time  the  ignition  that  the  greatest 
pressure  due  to  it  occurs  at  the  commencement  of  the 
working  stroke  at  all  speeds.  Therefore  the  usual 
practice  is  to  advance  the  spark  as  the  speed  of  the 
engine  increases,  and,  conversely,  to  retard  it  as  the 
speed  is  reduced.  Great  care  must  be  taken  to  avoid 
pre-ignition  *  with  its  attendant  damaging  effects.  If 
the  sparking  is  so  timed  that  ignition  occurs  after  the 
piston  has  started  on  its  working  stroke,  the  ignition 
is  said  to  be  retarded,  and  the  effect  of  this  is  to  reduce 
the  amount  of  work  done  in  the  cylinder  during  this 
stroke.  Engineers  are  able  to  examine  the  variation 
of  pressure  in  the  cylinder,  during  the  complete  cycle, 
by  using  an  instrument  called  an  indicator.  When 
using  the  ordinary  form  of  this  instrument,  a  pencil 
point  traces  out  a  curved  figure  on  a  sheet  of  paper  or 
card,2  as  it  is  called,  and  from  it  the  pressure  on  the 
piston  at  all  points  in  its  stroke  can  be  measured,  a 
mean  of  these  pressures  giving  the  mean  pressure 3 
throughout  the  stroke.  The  area  of  the  figure  formed 
by  the  expansion  and  compression  lines  (3  and  2,  Fig. 
12  4)  is  a  measure  of  the  work  done  during  the  stroke, 
whilst  the  area  of  the  figure  bounded  by  the  exhaust 
and  suction  lines  4  and  1  (same  Fig.),  represents  the 

but  if,  on  the  other  hand,  due  to  throttling  the  cylinder  is 
charged  with  only  half  a  full  volume  when  the  compression 
begins  (this  means  doing  negative  work  during  suction 
stroke),  then,  obviously,  the  compression  cannot  exceed 
2X15=30  pounds  per  square  inch. 

1  Refer  to  Article  43. 

2  The  ordinary  instrument  does  not  give  satisfactory  re- 
sults  at  very   high  speeds,   but  the  beautiful   Hospitalier- 
Carpentier  Manograph  indicates  efficiently  at  2000  to  3000 
revolutions. 

3  This  is  the  pressure  which  is  used  in   measuring  the 
indicated  horse-power  of  the  engine. 

4  The  Figs,  are  slightly  contorted,  so  that  all  the  lines 
may  be  clearly  seen. 


53  MOTOES   AND   MOTORING 

negative  work  done  by  the  engine  when  acting  as  a 
pump  during  the  suction  stroke.  The  indicator  dia- 
gram not  only  shows  the  behavior  of  the  working  fluid 
in  the  cylinder,  but  it  reveals  any  defect  in  the  valve 
setting,  timing  of  ignition,  and  general  action. 

42.  Late   Ignition. — The    diagram   (Fig.  13)   shows 
what  occurs  when  the  spark  is  retarded  to  reduce  the 
power  of  the  engine.     It  will  be  seen  that  the  piston  has 
traveled  to  nearly  half  stroke  before  the  highest  pres- 
sure (which  is  much  less  than  in  the  normal  case)  is 
reached,  the  smaller  area  of  the  part  2,  3,  showing  the 
reduced  amount    of    work    done,    although    the    same 
amount  of  mixture  may    have    been    drawn    into    the 
cylinder  as  for  Fig.  12;  but  the  rate  of  propagation  of 
the  flame  throughout  the  charge  is  slow  compared  with 
the  piston  velocity,  due  to  the  lower  compression,  and 
the  gases  are  only  partially  burned  when  allowed  to 
escape  by  the  exhaust,  their  temperature  and  pressure 
being  much  higher  than  in  the  normal  case;  indeed, 
the  temperature  is  often  so  high  that  the  long-con- 
tinued action  of  the  hot  gases  on  the  exhaust  valves 
ultimately  destroys  them.     Moreover,  this  is  obviously 
a   very  uneconomical   way  of  working,   as   about   the 
same  quantity  of  fuel  is  used  per  stroke  for  different 
powers,  so  all  this  shows  the  evil  of  governing  by  spark 
variation. 

43.  Pre-Ignition. — Fig.  14  shows  how,  when  the  mix- 
ture is  sparked  too  early   (pre-ignited),  the  explosion 
suddenly  sends  the  pressure  up  to  a  high  point,  before 
the  completion  of  the  compression  stroke,  tending  to 
stop  the  engine,  and  severely  straining  it.    This  action 
also  leads  to  a  certain  amount  of  negative  work  being 
done  in  the  cylinder  during  the  cycle,  as  it  will  be  seen 
that  more  work  is  done  by  the   piston    on    the    gases 
during  compression,  than  is  done  on  the  piston  during 
the  expansion  stroke.     This  negative  work  is  represented 
by  the  area  2,  3. 

44.  Back-Firing,    or    explosion    during   the    suction 
stroke  or  early  part  of  compression  stroke  (Fig.  15), 


MOTORS   AND   MOTOEING 


53 


ATMOS 


54  MOTOKS    AND   MOTOKITO 

sometimes  occurs.  It  is  caused  by  overheated  valves  or 
smoldering  exhaust  gases,  and  its  effect  upon  the 
piston,  etc.,  is  similar  to  that  just  explained  in  con- 
nection with  pre-ignition. 

It  will  now  be  convenient  to  consider  how  the  timing 
of  the  spark  is  actually  effected,  and  an  examination 
of  Fig.  16  will  help  us  in  this  matter,  it  represents  a — 

45.  Commutator  or  Current  Distributor  of  the  Pan- 
hard  type.  T  (Fig.  16)  is  the  end  view  of  the  half- 
speed  shaft,  and  M  that  of  the  disc,  made  of  a  non- 
conducting material,  usually  of  a  fibrous  character;  it 
is  keyed  to  shaft  T,  and  is  fitted  with  a  metal  plate  K, 
which  is  put  in  metallic  contact  with  the  shaft  T,  which 
is  in  the  electric  circuit,  by  means  of  a  screw  or  pin  N. 
The  shell  or  body  G  has  a  boss  at  the  back  which  is 
bored  to  fit  the  shaft,  so  that  its  arm  or  lever  C  can 
move  it  and  its  fittings  freely  in  either  of  the  directions 
shown  by  the  arrows;  into  the  projecting  bosses  HH 
insulating  sleeves  or  brush  holders  FF  are  screwed,  and 
into  these  again  the  brass  tubes  VV  are  screwed.  These 
tubes  contain  the  brushes  BB,  which  are  made  of  coiled 
wire  gauze,  held  in  contact  with  the  edges  of  the  disc 
by  the  helical  springs  SS,  which  press  against  the  brass 
split  caps  DD;  bolts  or  screws  00  clipping  the  cap  on 
the  tube,  the  wires  EE  placing  the  brushes  BB  in 
metallic  contact  with  the  coils.  Obviously,  this  com- 
mutator is  arranged  to  serve  two  cylinders  with  cranks 
side-by-side,  as  in  the  Mors  engine,  the  number  of 
bosses  HH  and  their  fittings  corresponding  with  the 
number  of  the  engine's  cylinders  (with  cranks  at  180°, 
the  bosses  would  of  course  be  at  90°  to  one  another). 
The  link  J  is  connected  to  the  working  handle  by 
suitable  rods,  wire  cables,  and  levers.  A  movement  of 
C  to  the  left,  as  can  be  seen,  will  cause  ignition  to  occur 
later,  or  the  spark  will  be  retarded,  just  as  a  movement 
in  the  opposite  direction  will  bring  the  brushes  nearer 
the  advancing  metallic  contact  piece,  and  hasten  igni- 
tion or  advance  the  spark. 


MOTOES   AND   MOTOEING 


55 


46.  Governing  and  Controlling  by  Throttling  the 
Mixture,  sometimes  called  charge  volume  throttling  (or 
governing  on  the  inlet),  is  the  system  which  is  by  far 
the  most  popular.  A  governor  of  the  crank-shaft  cen- 
trifugal type  is  fitted,  usually  on  the  half-speed  shaft, 

COMMUTATOR    OE    CUEEENT    DISTEIBUTOE 

(Panhard  Type)  FOE  CEANKS  SIDE  BY  SIDE 

I 


and  arranged,  in  the  majority  of  cars  now  in  use,  to 
actuate  a  throttle  valve  placed  in  the  induction  pipe 
of  the  cylinders,1 — this  valve  is  either  of  the  butterfly a 

lrThe   quantity   is   regulated   in   the   Duryea   and   Bollee 
cars  by  giving  the  inlet  valve  a  variable  lift. 
*The  tendency  of  many  engines  fitted  with  this  valve  is 


56  MOTORS   AND   MOTORING 

(as  shown  in  Fig.  6  at  T)  or  cylindrical  type.  It  is 
regulated  so  that  when  the  car  is  running  on  level 
ground  with  a  smooth  surface,  the  engine  is  working 
in  an  economical  manner;  the  governor  only  allowing 
sufficient  explosive  mixture  to  enter  the  cylinder  to 
produce  the  amount  of  work  that  the  resistance  due  to 
the  condition  of  the  road,  direction,  and  velocity  of  the 
wind  call  for.  Should  this  resistance  increase,  through 
any  of  the  causes  mentioned,  or  owing  to  the  car  coming 
to  rising  ground,  the  engine  slows  down  and  the  gov- 
ernor automatically  opens  the  throttle  to  enable  a  larger 
charge  to  pass  into  the  cylinder,  and,  conversely,  the 
governor  commences  to  close  the  valve  as  soon  as  the 
engine  begins  to  race  above  its  normal  speed.  Some 
engines  are  so  fitted  that  the  throttle  can  also  be  con- 
trolled by  hand  or  foot. 

47.  Accelerator. — To  enable  the  engine  to  exert  its 
maximum  power  for  hill-climbing,  an  arrangement 
called  an  accelerator  is  fitted;  it  is  merely  a  combina- 
tion of  levers,  wire  cable,  and  spring,  fixed  up  to  con- 
nect the  governor  to  either  a  lever  fitted  to  the  steering 
column,  or  to  a  pedal  projecting  through  the  foot-board 
(the  latter  being  the  more  usual  arrangement),  so  that 
by  a  movement  of  the  lever  or  pedal,  the  weights  of  the 
governor  are  prevented  from  exerting  their  power  to 
close  the  throttle;  in  other  words,  it  cuts  out  the  gov- 
ernor's action,  the  throttle  remaining  open,  allowing 
the  speed  of  the  engine  to  increase  above  its  normal 
rate,  and  the  engine  to  work  at  its  maximum  power, 
which  is  obviously  what  is  required  if  a  steep  grade  is 

to  run  in  jerks,  first  gaining  speed,  then  slowing  down  too 
much  under  the  action  of  the  governor,  or,  in  other  words, 
the  governor  hunts;  but  this  un-uniform  action  has  been 
largely  checked,  and  the  running  much  improved,  by  drilling 
a  hole  about  \  inch  in  diameter  through  the  disc  of  the 
valve,  to  form  a  by-pass.  Probably  in  some  cases  the  uni- 
formity of  running  would  be  much  improved  by  the  gov- 
ernor being  fitted  with  a  dash-pot  arrangement,  but  at  the 
best,  with  light  loads,  throttle  governing  is  more  or  less 
unstable. 


MOTORS   AND   MOTORING  57 

to  be  mounted  without  changing  gear;  but  should  the 
car  then  fail  to  make  headway,  the  gear  is  changed 
to  a  lower  one,1  and  the  accelerator  is  thrown  out  of 
action,  allowing  the  governor  to  act  again,  and  the 
engine  to  run  at  its  normal  speed.  The  accelerator 
should  never  be  used  unless  really  required  if  the 
engine  is  to  be  economically  worked. 

48.  Governing  on  the  Exhaust. — In  this  system  a  hit 
and  miss  arrangement,  actuated  by  a  centrifugal  gov- 
ernor of  the  crank-shaft  type,  permits  the  exhaust  valve 
to  be  raised  in  the  ordinary  way  when  the  engine  is 
working  within  its  maximum  speed  limit,  but  when  the 
latter  is  reached  a  digger  is  withdrawn  from  the  exhaust 
valve  spindle  or  plunger  by  the  action  of  the  governor, 
so  that  the  valve  remains  unlifted,  and  the  burnt  charge 
is  retained  within  the  cylinder;  or  the  opening  of  this 
valve  is  retarded,  a  portion  of  the  burnt  gases  remaining 
in  the  cylinder  to  dilute  the  next  charge  admitted. 
This  so  reduces  the  speed  of  the  engine,  that  the  next 
exhaust  stroke  is  a  normal  one,  and  the  ordinary  cycle 
of  operations  is  taken  up  again.  With  this  system  there 
is,  of  course,  a  loss  due  to  back  pressure,  but  the  cylinder 
being  kept  full,  the  compression  does  not  suffer,  and  the 
mixture  is  therefore  more  economically  consumed, 
although,  when  the  engine  runs  light,  there  is  a  loss  of 
economy,  as  the  incoming  cold  charge  mingles  with  the 
hot  burnt  gases,  making  a  high  temperature  mixture 
before  compression.  Not  a  little  of  the  economy  of  the 
Gillet-Foust,  and  other  motors,  is  claimed  for  this  sys- 
tem of  governing,  and  it  is  thought  much  of  by  some 
whose  opinions  are  entitled  to  respect,  although  it  has 
practically  died  out,  and  is  only  now  seen  on  old  cars 
which  are  still  running. 

1  Drivers  easily  get  into  a  way  of  manipulating  the  clutch 
to  enable  them  to  mount  the  crest  of  rising  ground  without 
changing  gear.  As  the  engine  slows  down,  the  clutch  is 
momentarily  withdrawn  to  allow  the  engine  to  gain  speed, 
and  is  let  in  again  before  the  car  has  had  time  to  be  much 
reduced  in  speed.  For  obvious  reasons  this  expedient  must 
be  worked  with  moderation. 


58  MOTORS   AND   MOTORING 


CYLINDER   COOLING 

49.  When  it  is  remembered  that  somewhere  in  the 
cylinder  during  each  working  stroke  there  may  be  a 
temperature  of  some  3600°  F.,  tapering  off  to  about 
1800°  to  2000°  F.  as  the  burnt  gases  pass  out  of  the 
cylinder,  and  that  the  temperature  of  the  cylinder-wall 
must  be  low  enough  to  allow  of  the  piston  being  effi- 
ciently lubricated,  the  importance  of  providing  suitable 
arrangements  for  keeping  the  cylinder  sufficiently  cool 
can  be  realized.  To  make  the  conditions  under  which 
the  piston  can  satisfactorily  work  in  the  cylinder  a  little 
more  clear,  it  should  be  explained  that  the  maximum 
temperature  referred  to  is  more  or  less  evolved  at  the 
kernel  of  the  mixture,  the  temperature  near  the 
cylinder-wall  probably  being  not  much  more  than  half 
that  amount,  and  that  of  the  wall  itself  about  250°  F. 
Further,  these  high  temperatures  are  much  reduced 
during  the  suction  stroke,  when  the  cool  mixture  enters, 
also  during  the  compression  stroke,  although  not  to  the 
same  extent,1  so  that  the  heat  imparted  to  the  cylinder 
each  cycle  is  not  so  much  as  might  at  first  be  expected ; 
nevertheless,  as  an  engine  making  1000  revolutions  a 
minute  will  perform  a  cycle  in  V500  of  a  minute,  or 
rather  less  than  |  of  a  second,  the  rapid  succession  of 
heat  increments  could  soon  raise  the  temperature  of  the 
cylinder  to  a  point  when  effective  lubrication  would  be 
impossible,  so  to  keep  the  temperature  of  the  cylinder 
down  to  a  safe  point,  special  arrangements  have  to  be 
made.  So  far  as  very  small  engines  (such  as  are  used 
on  low-power  motor  bicycles)  are  concerned,  it  is  suffi- 
cient to  increase  the  outer  surface  of  the  cylinder,  by 
an  arrangement  of  either  radiating  or  circular  flanges 
or  ribs,2  so  that  in  passing  through  the  air  it  may  be 
cooled  as  much  as  possible.  The  cooling  efficiency  of 

*A  great  deal  of  heat  is  generated  in  compressing  the 
mixture. 

2  Circular  flanges  are  best,  as  the  air  can  more  completely 
sweep  round  them,  and  they  materially  add  to  the  strength 
of  the  cylinder. 


MOTOES   AND   MOTOEING  59 

this  arrangement  (or  of  the  air-cooled  tubes  of  a 
radiator)  depends  upon  the  velocity  of  the  encountering 
air,  the  extent  of  the  surface  in  contact  with  that  air, 
and  the  difference  in  temperature  between  the  inner 
surface  and  the  air  in  contact  with  the  exterior  surface. 
It  is  found  that  when  this  simple  method  is  intelligently 
carried  out,  the  cylinders  of  engines  up  to  about  3  horse- 
power can  be  effectively  cooled,  but  with  larger  powers 
the  problem  becomes  one  that  requires  the  assistance 
of  an  additional  cooling  agency  to  solve  it;  hence  the 
evolution  of  the  arrangement  diagrammatically  shown 
in  Fig.  1,  where  it  will  be  seen  that  the  cylinder  has  a 
jacket  surrounding  it,  through  which  water  is  circu- 
lated l  by  a  centrifugal  pump2  (P.O.)  which  forces 
the  water  to  circulate  through  the  cooling  system, 
entering  the  jacket  at  the  lowest  part  a,  and  leaving  it 
at  the  top  Jj,  passing  through  the  connecting  pipe  3  into 
the  radiator  to  the  tank  4  at  a  level  of  about  its  center  c, 
and  leaving  it  at  its  bottom  d  to  enter  the  pump  again. 

1  There   is   another   system   in   use,   in  which   cooling  is 
effected  by  water  evaporation  within  the  jacket 

2  This  pump  is  found,  on  the  whole,  to  be  the  most  satis- 
factory for  the  purpose.     If  made  a  decent  size,  not  requir- 
ing to  be  run  at  a  high  speed,  and  gear  driven,  as  many  now 
are,  it  works  well,  and  is  not  affected  by  dirt  in  the  water. 
Other  types,  such  as  the  rotary-force  and  the  simple  gear, 
have  been  tried  and  used  by  a  few  makers,  but  although 
they  give  an  excellent  circulation  when  perfect,  they  soon 
wear  out,  and  their  first  cost  is  greater,  to  say  nothing  of 
the  difficulty  of  keeping  their  wearing  parts  lubricated  with- 
out introducing  into  the  cylinder  jacket  and  tubes  an  oily 
viscous  coating  that  much  impairs  their  efficiency. 

3  These  pipes  are  often  made  too  small,  and  with  bends 
much  too  sharp,  to  allow  of  a  free  and  unrestricted  circula- 
tion.    They  should  not  be  less  than  f  inch  diameter,  and  the 
bends  should  have  a  radius  of  at  least  some  five  diameters 
when  practicable. 

4  The  connections  c  and  d  to  the  tank  should  be  as  far 
away  from  one  another  as  possible ;  so  as  to  get  a  good  cir- 
culation of  water  in  the  tank,  they  are  usually  placed  at 
opposite  ends,  as  shown.     The  tank  is  fitted  with  a  filling 
hole,   usually  covered  with  a  screwed  bung,   and  an  open 
tube  from  the  highest  part,  bent  over  the  tank  side  to  allow 
any  steam  that  may  be  generated  to  escape. 


60  MOTOES   AND   MOTOKING 

If  the  tank  and  radiator  be  sufficiently  large,  and  fixed 
high  enough  above  the  engine,1  a  very  fair  natural  cir- 
culation results  without  using  a  pump;  in  fact,  this 
gravity  or  thermo-syphon  system  has  the  great  advan- 
tage of  simplicity  to  recommend  it,  and  formerly  was 
much  used,  and  still  is  used  with  advantage  on  very 
light  cars.  Thus  the  introduction  of  forced  circulation, 
with  the  indispensable  pump,  which  in  some  form  or 
another  is  general,  has  reduced  the  weight  of  the  cool- 
ing system,  and  increased  its  efficiency,  but  has  added 
to  the  number  of  parts  which  require  attention  and  are 
liable  to  give  trouble.  The  cooling  system  being  a 
vital  part  of  the  motor,  it  greatly  reduces  the  possibility 
of  annoying  stoppages  when  fitted  so  that  in  case  of 
emergency  the  pump  can  be  thrown  out  of  circuit,  and 
the  engine  run  on  low  speed  and  power  with  natural 
or  gravity  circulation. 

50.  Radiators. — There  are  two  types  of  radiators  in 
use,  namely,  the  multitubular  and  coil.  The  former 
was  first  brought  out  on  the  famous  Mercedes  car.  In 
this  the  water  is  made  to  circulate  around  a  great  num- 
ber (in  some  cases  amounting  to  5000  or  6000)  of  small 
tubes  fixed  about  1/16  of  an  inch  apart,  its  principal 
advantage  being  the  small  volume  and  weight  of  water 
used,  some  few  pints  only  being  required.  Its  draw- 
backs are  that  the  workmanship  must  be  of  the  very 
highest  class,  or  leakage  troubles  will  occur.  Eadiators 
of  this  type  are  very  difficult  to  repair,  and  the  pas- 
sages being  so  very  small,  they  are  liable  to  get  choked. 
In  the  other  or  ordinary  type,  the  well-known  ribbed 
or  gilled  pipe  coil,  the  section  of  the  pipe  is  usually 
circular,2  and  the  surface  of  the  gills  flat,  although 

1  Vibration,  and  the  slight  yielding  of  the  frame  when  the 
car  is  roughly  used,  cause  the  connections  to  become  leaky ; 
so,  for  this  reason,  armored  rubber  hose  is  to  be  preferred 
for  the  connections,  which  should  always  be  long  enough  to 
prevent  undue  straining  actions. 

2  A  flattened  tube  has  a  larger  cooling  surface  than  a  cir- 
cular one  of  the  same  sectional   area,  but  it  offers  more 
resistance  to  the  flow  through  it,  particularly  at  the  bends. 


MOTOES    AND   MOTOBDTG  61 

some  of  the  latter  are  corrugated,  the  idea  being  that 
as  they  expose  more  surface  to  the  action  of  the  air, 
they  are  more  efficient,  but  it  has  been  proved  that  this 
is  not  the  case,  the  corrugations  retarding  the  passage 
of  air  between  them,  and  causing  as  much  loss  of  cooling 
effect  as  was  gained  by  the  extra  surface.  With  either 
type  a  float-glass,  in  which  the  position  of  the  float 
indicates  the  condition  of  the  circulation,  is  fixed  to  the 
dash-board,  or  the  water  passes  through  a  glass  tube 
fixed  there,  so  that  the  condition  of  the  circulation  can 
be  seen  at  a  glance. 

51.  Air  Fans  are  now  generally  used,  but  unless  these 
be  skillfully  designed,  and  run  at  a  speed  sufficiently 
high    (which,  by  the  way,  requires  a  fair  amount  of 
power),  they  can  easily  be  worse  than  useless.1     Indeed, 
in  not  a  few  cases  that  the  writer  has  come  across,  the 
efficiency  of  the  motor  would  have  been  increased  by 
scrapping  the  fan  and  paying  a  little  more  attention  to 
the  condition  of   the    surface    of   the    radiator,  which 
should  be  so  treated  that  heat  leaves  it  with  the  greatest 
freedom.      Now,    strangely    enough,    all    bright    and 
polished    surfaces    reluctantly   part   with    their    heat,2 
whilst  most  dull  rough  ones  freely  lose  it,  therefore  the 
common  practice  of  blackleading  and  polishing  cylin- 
ders and  cooling  pipes,  or  coating  them  with  metallic 
paints,   impairs   the   efficiency   of   the   rough   surface. 
The  best  stuff  known  for  coating  purposes  is  lampblack, 
and  the  rougher  the  surface  to  which  this  is  applied, 
the  more  easily  will  it  part  with  its  heat. 

52.  Air-Locking. — Trouble  sometimes  occurs  due  to 
the  system  becoming  air-locked  in  filling  up  with  water, 
an  air-bubble  forming  in  the  top  of  a  bend  and  getting 
compressed   and  set   instead  of   circulating   when  the 
pump  begins  to  work.     This  of  course  means  that  the 
flow  of  water  is  stopped,  with  consequent  boiling  away 

1  They  also  draw  the  dust  from  the  roads,  and  the  hot  air 
off  the  radiators  on  to  the  engine,  which  is  a  drawback. 

2  Part  of  the  heat  is  carried  or  conducted  away  by  the  air 
in  contact  with  the  surfaces,  and  part  by  radiation. 


62  MOTOKS   AND   MOTOEING 

of  that  portion  of  the  water  which  is  kept  in  contact 
with  the  cylinder,  it  not  being  free  to  pass  through  the 
radiator,  which  quickly  becomes  hotter  at  the  upper 
part  than  at  the  bottom;  so,  if  a  sensible  difference  of 
temperature  be  detected  in  these  parts  after  the  engine 
has  been  running  a  few  minutes,  it  means  that  there  is 
either  an  air-lock  or  the  pump  is  not  working;  if  the 
former,  it  may  sometimes  be  relieved  by  opening  the 
air-cock,  which  is  generally  fitted  to  the  top  of  the 
radiator,  or,  this  failing  to  give  relief,  by  drawing  off 
the  water  and  continuing  to  fill  up  the  tank  while  the 
engine  is  running  slowly. 

MUFFLERS 

53.  No  one  can  fail  to  have  noticed  what  a  marked 
improvement  has  been  made  during  the  past  year  or 
two  in  muffling,  or  deadening,  the  sound  of  the  exhaust 
gases  from  gasolene  motors,  and  all  must  agree  that  this 


TYPICAL   MUFFLER 


Fig.  v. 

.is  a  step  in  the  right  direction,  indeed,  one  well  worth 
making  if  we  have  not  to  pay  too  dearly  for  it  in  greatly 
reduced  effective  power,  which  is  the  price  represented 
by  want  of  skill  in  designing  the  silencer.  The  problem 
to  be  solved  is,  how  to  deaden  the  noise  caused  by  the 
sudden  liberation  of  the  exhaust  gases  under  pressure. 
The  engine,,  as  used  at  the  present  time>  emits  the 


MOTOKS   AND   MOTOKING  63 

products  of  combustion  at  such  a  pressure  that  they 
expand  violently,  striking  the  surrounding  air,  and 
causing  the  sensation  which  we  know  as  a  noise  or 
explosion.  Now,  the  silencing  method  usually  adopted 
is  to  muffle  this  noise  by  passing  the  gases  into  a 
cylinder  of  considerable  capacity,  to  allow  them  to 
expand  with  little  resistance  till  their  pressure  is  equal 
to  that  of  the  atmosphere;  their  path  through  the 
cylinder  being  made  more  or  less  tortuous  by  baffles  and 
perforated  pipes,  with  the  object  of  breaking  up  the 
sound-waves  and  reducing  their  velocity,  so  that  the 
gases  pass  out  of  the  silencer  nearly  inert  and  noiseless. 

Another  principle  has  been  applied  lately  with  a  fair 
amount  of  success;  the  gases  are  discharged  through  a 
large  number  of  little  holes  in  a  muffler  of  very  small 
dimensions,  the  idea  being  to  break  up  the  large 
explosion  into  very  many  small  ones,  which,  not  syn- 
chronizing, more  or  less  cancel  one  another.  But  any 
attempt  to  reduce  the  dimensions  of  the  muffler  below 
a  certain  capacity,  which  depends  upon  size  of  the  cylin- 
der and  pressure  of  the  gases  as  they  leave  the  exhaust 
valve,  must  mean  an  increase  of  back  pressure.  Some 
cars  are  fitted  with  a  by-pass  valve,  so  that  the  driver 
can  temporarily  allow  the  gases  to  escape  without  all 
passing  through  the  muffler,  thereby  reducing  the  back 
pressure,  and  giving  the  motor  a  little  extra  power  when 
required. 

A  very  good  idea  of  how  a  typical  muffler  works  can 
be  formed  by  examining  Fig.  17,  where,  if  the  arrows 
be  followed,  it  will  be  seen  that  the  gases  pass  through 
in  a  zig-zag  way,  increasing  in  volume,  and,  therefore, 
decreasing  in  pressure,  as  they  near  the  outlet  to  the 
atmosphere  at  the  end  B. 

54.  Back-Firing  or  Popping  in  the  muffler  is  nearly 
always  caused  through  the  mixture  being  too  weak;  the 
charge  is  not  then  exploded  in  the  cylinder,  but  passes 
out  of  the  exhaust  valve  into  the  muffler,  where  it  is 
ignited  by  the  heat  of  the  exhaust  pipe  or  passages. 
When  the  speed  of  a  motor  is  suddenly  checked,  the 


64  MOTOES    AND    MOTOKING 

piston  does  not  move  quick  enough  to  suck  in  a  suffi- 
cient quantity  of  spray  to  carburate  the  air,  so  the 
remedy  is  to  push  the  mixture  lever  forward  when  sud- 
denly reducing  speed. 


TRANSMISSION  GEAR 

55.  If  a  side  view  of  the  engine  in  Fig.  1  had  been 
shown,  it  would  have  been  seen  that  the  crank-shaft  is 
fitted  with  a  fly-wheel,  whose  function  in  a  reciproca- 
ting engine  is  well  understood,  as  most  people  are  aware 
that  not  a  little  of  the  even  running  of  a  gasolene  en- 
gine, with  its  one  working  stroke  in  four,  is  due  to  this 
important  part  being  of  sufficient  size  and  weight.  Of 
course  it  is  keyed  to  the  tail  of  the  crank-shaft,  as  shown 
in  Fig.  18  at  D,  and  in  most  cases  it  is  made  with  a 
conical  hole  arranged  to  form,  with  the  male  conical 
block  C,  a  friction  clutch.  This  clutch  is  used  to  con- 
nect the  road  wheels  with  the  motor  through  a  mechan- 
ism called  the  transmission  gear.  And  two  forms  of 
this  gear  now  hold  the  field,  one,  called  chain  gear,  in 
which  side  chains  are  used  to  drive  the  back  road  wheels, 
which  are  loose  on  the  axle,  and  the  other  in  which  the 
power  is  transmitted  to  the  back  axle,  by  tooth  gearing, 
causing  it  to  rotate  and  carry  with  it  the  rear  road 
wheel's,  which  are  in  this  case  fixed  to  it.  To  understand 
these  arrangements,  and  to  be  clear  about  what  hap- 
pens when  a  car  is  reversed,  or  put  on  a  different  speed 
by  a  change  of  gear,  the  reader  is  referred  to  Figs.  18 
and  19,  which  diagrammatically  show  typical  examples 
of  these  gears.  The  former  illustrates  the  system  of 
Driving  through  Side-Chains,  and  it  will  be  seen  that 
the  male  part  C  of  the  clutch  is  kept  in  frictional  con- 
tact with  the  fly-wheel  part  D,  by  the  action  of  the  com- 
pressed helical  spring  S,  the  friction  between  them  due 
to  the  spring  being  great  enough  to  enable  the  engine 
to  drive  the  car  through  the  clutch.  A  bell-crank 
lever,  with  a  fork  at  one  end  and  a  pedal  at  the  other,  is 


MOTOES    AND   MOTORING  65 

fitted  to  the  grooved  collar  M,  as  shown  in  Fig.  20,  in 
such  a  way  that  when  the  pedal  G  is  pushed,  the  spring 
is  compressed  and  the  clutch  thrown  out  of  action. 
Now,  although  this  small  end  movement  of  the  clutch 
cone  C  in  relation  to  the  shaft  N  can  take  place,  they 
are  so  coupled1  that  when  C  is  "  let  in,"  and  is  rotating 
about  the  axis,  the  shaft  N  is  made  to  turn  with  it. 
Keyed  to  N  (Fig.  18)  are  three  wheels,  E,  B,  and  P  (E 
and  B  are  used  for  running  ahead,2  and  P  for  revers- 
ing), each  of  which  is  arranged  to  mesh  with  one  of 
the  wheels  on  the  sleeve  GO.  Now  this  sleeve  is  usually 
made  with  a  square  hole  fitting  the  shaft  RV,  which 
is  square  to  fit  it.3  The  sleeve  has  on  it  a  grooved  col- 
lar, which  engages  a  sliding  fork  F,  suitably  connected 
at  L,  to  the  change-speed  lever  fixed  at  the  right  hand 
side  of  the  car,  and  this  lever  works  in  a  quadrant  with 
four  notches,  one  of  these  corresponding  to  the  position 
of  the  sleeve  shown  with  the  second  speed  *  wheels  in 
mesh. 

Another  position  (due  to  a  movement  of  L  towards 
the  right,  and  the  lever  into  another  notch)  places  the 
first  speed  wheels  G  and  E  in  mesh,  whilst  a  movement 
of  L  to  the  left  throws  all  the  wheels  out  of  mesh,  and 
the  engine  is  free  to  rotate  without  driving  the  shaft 
VR.  This  of  course  is  the  position  of  the  sleeve  when 
the  car  is  standing  still  and  the  engine  is  running,  the 
change-speed  lever  being  in  the  neutral  notch.  The 
fourth  notch  fixes  the  position  of  the  lever  for  reversing 
the  car.  When  this  notch  is  used,  the  sleeve  is  moved 

lrThe  clutch  C  driving  the  shaft  N  through  a  feather 
fitted  to  the  latter. 

2  It  will  be  noticed  that,  for  simplicity's  sake,  the  gear-box 
in  this  example  only  contains  two  pairs  of  forward  wheels 
and  a  reverse,  corresponding  to  two  speeds  of  the  car  for 
a  given  speed  of  the  engine.  Of  course,  a  motor  arranged 
in  this  way  would  be  more  dependent  upon  the  elasticity 
of  the  engine  (or  power  of  varying  its  speed)  than  one 
fitted  with  three  or  four  speeds. 

8  Or  the  shaft  is  round,  and  fitted  with  a  feather  arranged 
to  drive  the  sleeve. 

4  In  this  case  the  highest  speed. 


MOTORS    AND   MOTORING  67 

to  the  left  till  the  wheels  0  and  P  are  opposite.  0  then 
comes  into  mesh  with  another  wheel,  called  a  change 
wheel,  running  on  a  third  shaft  above  it  (not  shown 
in  the  Fig.)  which  connects  the  two  wheels,  but  causes 
the  wheel  0  and  the  shaft  VE  to  rotate  in  same  direc- 
tion, thus  reversing  the  car. 

It  should  hardly  be  necessary  to  explain  that  the  shaft 
VE  drives  the  differential  shaft  DS,  through  the  bevel 
wheels  J  and  H  and  the  box  D  containing  the  differen- 
tial gear1;  the  shaft  DS,  in  its  turn,  driving  the  road 
wheels  through  the  chains  as  shown,  and  in  the  way  that 
everyone  who  owns  a  common  bicycle  understands. 

The  other  kind  of  transmission  gear  referred  to  is 
the— 

56.  Live-Axle  or  Cardan  Drive,  in  which  the  power 
of  the  engine  is  transmitted  to  the  road  wheels  by  tooth- 
gear  throughout.  This  system,  which  is  becoming  in- 
creasingly popular,  can  be  understood  by  an  examina- 
tion of  the  explanatory  diagram  Fig.  19.  It  will  be 
noticed,  that  from  the  motor  to  the  gearing  box  GB, 
the  mechanism  is  the  same  as  in  Fig.  18;  indeed,  the 
greater  part  of  the  gear  and  box  is  identical  with  that 
previously  described  in  connection  with  that  figure,  but 
in  Fig.  19  the  tail  of  the  shaft  GE  is  connected  to  the 
bevel  pinion  c  by  the  propeller  or  Cardan  shaft  ps,  two 
flexible  or  universal  joints  2  a  and  b  being  fitted  to  the 
shaft  to  allow  full  play  of  the  carriage-spring  system 
between  the  road-wheel  axle  and  the  frame  which  sup- 
ports the  motor  and  gear-box. 

Now  the  bevel  pinion  c  is  in  mesh  with  the  bevel 
wheel  d,  which  forms  part  of  the  differential  gear-box 
T,  through  which  motion  is  transmitted  to  the  axle  of 
the  driving  wheels. 

^ne  form  of  this  Interesting  and  indispensable  gear  is 
shown  in  section  on  the  live-axle  in  Fig.  19,  and  its  action 
is  referred  to  in  the  next  article. 

2  These  joints  are  perhaps  best  known  as  Hooke's,  the 
inventor  being  Dr.  Hooke,  the  famous  scientist.  They  are 
also  sometimes  called  Cardan  joints. 


MOTORS   AND   MOTORING  69 

It  will  now  be  convenient  to  give  a  little  attention  to 
some  of  the  details  that  have  been  referred  to  in  con- 
nection with  the  two  systems  of  transmission,  so  we 
may  commence  with — 

57.  The  Differential  Gear,  which  is  a  train  of  wheels 
elegantly  arranged  to  average  the  speeds  of  the  two 
driving  wheels,  for,  when  the  car  turns  a  corner  or  runs 
round  a  bend  in  the  road,  the  outer  road  wheel  will  be 
traveling  faster  than  the  inner  one;  but  the  propeller 
shaft  can  only  revolve  at  one  speed  at  any  given  mo- 
ment, and  that,  therefore,  must  be  the  average  of  the 
two  speeds,  due  to  the  running  of  the  inner  and  outer 
road  wheel.     Although  it  is  not  easy,  without  suitable 
drawings,  to  make  clear  to  the  general  reader  how  this 
arrangement  works,  the  following  experiment  will  help 
him,  at  any  rate,  to  understand  the  function  of  this 
important  fitting.     Jack  up  the  road-driving  wheels  to 
clear  the  ground,  place  the  change-speed  lever  in  the 
neutral  notch,  then  turn  by  hand   one   of   the  road 
wheels  n  (Fig.  19),  and  the  other  wheel  ra  will  revolve 
in  the  opposite  direction  at  the  same  speed,  the  average 
speed  being  zero.     Again,  let  one  of  the  wheels,  say  n, 
be  fixed,  and  the  bevel  wheel  d  be  turned,  it  will  be 
found  that  the  other  road  wheel  m  will  revolve  at  twice 
the  speed  of  d  1  or  the  speed  of  d  is  the  average  of  the 
speeds  of  m  and  n,  as  before.     And  so,  if  in  turning  a 
corner  n  revolved  at  70  a  minute  and  m  at  80,  d  would 
be  running  at  the  mean  or  average  75. 

One  of  the  most  important  details  of  a  transmission 
gear  is — 

58.  The  Clutch,  as  at  any  moment,  when  a  car  is  run- 
ning, the  safety  of  the  vehicle,  indeed,  the  safety  of  the 

1  The  box  T  revolving  with  the  bevel  wheel  d  carries  with 
it  the  two  (or  more)  bevel  pinions  (called  epicyclic,  owing 
to  their  movement  around  the  axis  of  motion)  e  and  f, 
which,  being  in  mesh  with  the  stationary  pinion  h,  cause 
the  pinion  g,  and  the  axle  i  to  which  it  is  fixed  (h  being 
also  fixed  to  axle  ;),  to  revolve  at  twice  the  speed  of  d,  the 
pinion  g  being  carried  round  once  by  e  and  /  and  driven 
once  by  being  in  mesh  with  h. 


70  MOTORS   AND   MOTORING 

occupants,  may  be  jeopardized  by  its  faulty  action,  for, 
when  in  working  order,  a  push  on  the  pedal  instantly 
disconnects  the  motor  from  the  transmission  gear,  and 
the  car  can  be  stopped  by  an  application  of  the  brakes; 
but  should  the  clutch  seize  at  a  critical  moment,  this 
release  cannot  be  made  without  a  deal  of  trouble,  and 
it  is  easy  to  imagine  what  might  happen.  Fortunately, 
this  is  a  mishap  which  rarely  occurs,  indeed,  should 
never  occur,  if  the  clutch  is  made  with  a  suitable  taper, 
and  care  is  taken  in  a  metal  to  metal  contact  to  keep  the 
surfaces  lubricated.  In  this  connection  it  should  be  ex- 
plained that  the  surfaces  of  the  male  cone  is  generally 
faced  with  leather,1  to  increase  the  amount  of  friction, 
copper  being  occasionally  used  instead.2 

59.  Fierce  Clutches. — Clutches  may  cause  trouble, 
either  by  slipping  too  much3  or  by  not  slipping  enough ; 
in  the  latter  case  they  are  said  to  be  fierce,  and  the  cause 


1  The  leather  is  usually  riveted  to  the  conical  surface  of  the 
male  part  of  the  clutch  by  copper  rivets.     These  are  first 
screwed  into  the  cone  and  hammered  down,  till  the  heads 
are   rather   more   than   £   inch   below   the   surface   of   the 
leather,    the    holes    in    the    latter    having   been    previously 
countersunk.     When  the  riveting  is  completed,  a  light  cut 
is  taken  off  the  leather  in  a  lathe,  so  that  its  surface  is  truly 
conical  and  the  right  taper.     The  leather  ultimately  wears 
down  to  the  rivets,  and  when  this  occurs,  the  clutch  is  apt 
to  become  very  fierce,  owing  to  the  rivet  heads  seizing  the 
metal  of  the  clutch ;  they  then   require  hammering  down 
till  they  are  well  below  the  surface  again. 

2  There  appears  to  be  a  growing  tendency  to  dispense  with 
a  facing,  and  run  the  clutch  with  bare  iron  contact. 

3  Slip  may  be  due  to  too  much  oil  getting  on  to  the  leather 
face ;   this  may  be  remedied  by  applying  a   little  Fuller's 
earth,   chalk,   or   lime.     But  slip  may   also  be  due  to   the 
spring  being  too  weak ;  if  this  be  the  cause,  the  spring  must 
be  further  compressed  by  screwing  up  the  adjusting  nut. 
The  clutch  should  be  so  adjusted  that  it  is  just  on  the  point 
of  slipping  when  the  car  is  exerting  its  full  power  in  mount- 
ing a  hill  on  its  lowest  speed.    Often  this  means  a  good  deal 
of  strain  on  the  ankle  for  a  long  run,  and  the  temptation  to 
ease  the  spring  is  great,  but  it  should  be  remembered  that 
slip  means  loss  of  power. 


MOTORS   AND   MOTOEINQ  71 

is  either  the  presence  of  gritty  dirt  on  the  leather,1  or 
the  spring  being  too  strong.  If  due  to  dirt,  the  leather 
should  be  washed  with  gasolene,  and  dressed  with  a  small 
quantity  of  castor  or  Collan  oil;  this  makes  and  keeps 
the  leather  soft  and  pliable,  and  allows  the  necessary 
slip  to  take  place  should  the  clutch  be  accidentally 
allowed  to  too  suddenly  engage.  If  this  treatment  does 
not  improve  matters,  and  the  clutch  takes  up  its  work 
too  rapidly,  causing  the  car  to  plunge  forward,  subject- 
ing the  whole  vehicle  to  abnormal  strains,  instead  of 
gradually  moving  off,  as  it  should  do,  then  the  com- 
pression of  the  spring  must  be  relieved  by  unscrewing 
the  adjusting  nut  to  increase  its  length.  A  little  pa- 
tient attention  to  these  matters  will  enable  the  driver, 
by  a  give  and  take  correction,  to  put  the  clutch  in  proper 
working  order.  Of  course,  with  a  conical  clutch  as 
ordinarily  arranged,  there  is  a  certain  amount  of  thrust 
in  both  directions,  due  to  the  spring,  which  requires  at- 
tention, this  being  sometimes  taken  on  ball  bearings; 
and  it  is  owing  to  this  that  expanding  clutches,  which 
cause  little  or  no  thrust,  are  coming  into  use,  but  the 
difficulty  has  been  ingeniously  overcome  in — 

60.  The  Panhard  Clutch,  which  is  diagrammatically 
shown  in  Fig.  20.  It  will  be  seen  that  in  this  arrange- 
ment the  dished  fly-wheel  F  is  bolted  on  to  the  tail  of 
the  crank-shaft  CS,  which  is  flanged  at  A  for  that  pur- 
pose. Through  the  rim  of  the  fly-wheel,  pins  PP  are 
fastened,  the  projecting  parts  passing  through  holes  in 
the  flange  of  the  male  cone  C  to  enable  the  fly-wheel  to 
drive  the  latter.  The  female  cone  B  is  attached  to  the 
hollow  clutch  shaft  N,2  so  that  when  the  clutch  is  en- 
gaged, the  helical  spring  S  presses  the  grooved  collar 
M  against  the  cone  C,  forcing  it  into  cone  B,  and  in  so 

1  Fierceness  is  also  caused  by  renewing  the  leather  fac- 
ing ;  the  remedy  is,  apply  the  clutch  gently  until  the  leather 
wears  down  and  becomes  fairly  smooth. 

2  This  shaft  is  usually  coupled  to  the  change-gear  shaft 
N  (Fig.  18)  by  a  sleeve,  inside  of  which  is  a  distance  price, 
so  that  by  opening  the  coupling  sleeve  and  removing  the 
distance  price,  the  clutch  and  shaft  can  be  removed. 


72  MOTORS   AND  MOTORING 

doing  creating  friction  enough  to  enable  the  car  to  be 
driven  through  the  clutch.  The  reaction  at  the  other 
end  of  the  spring  is  exerted  by  the  adjustable  collar-nut 
D,  so  that  the  opposite  forces  are  completely  balanced, 
without  any  thrust  being  thrown  on  the  crank-shaft  or 
gear-box.  This  balance,  it  should  be  explained,  is  dis- 

PANHARD  CLUTCH. 


turbed  when  the  pedal  G  is  pushed  to  disengage  the 
clutch,  an  additional  pressure  is  then  exerted  on  the 
collar  D,  thrusting  the  shaft  N  to  the  right,  but  a 
thrust  block  E  is  arranged  to  receive  that.  There  is 
also  a  thrust  bearing  at  0  to  transmit  the  thrust  of 
the  spring  to  the  cone  C.  It  will  be  noticed  that  the 


MOTORS   AND   MOTORIKO  73 

cone  end  of  the  shaft  fits  into  the  boss  R  of  the  fly- 
wheel, thereby  keeping  the  shafts  in  perfect  alignment, 
which  is  a  most  important  condition  to  satisfy.  In 
some  cars,  such  as  the  Canstatt  Daimler,  and  the  Mer- 
cedes Simplex,  the  withdrawal  of  the  clutch  automati- 
cally reduces  the  speed  of  the  engine,  whilst  in  most 
cases  the  act  of  applying  the  foot-brake  disengages  the 
clutch. 

61.  Gear  Changing. — In  the  case  of  cars  fitted  with 
the  ordinary  or  Panhard  gear,  one  of  the  most  delicate 
operations  the  driver  has  frequently  to  perform  is  gear 
changing,  for  if  this  is  not  done  with  sufficient  skill  and 
.  care,  the  teeth  of  the  wheels  are  apt  to  be  seriously  dam- 
aged and  the  car  abnormally  strained.  We  have  seen 
that  in  changing  from  one  gear  to  another,  the  teeth  of 
the  wheels  which  are  in  mesh  have  to  be  disengaged  and 
those  of  others  put  into  mesh  by  a  sliding  movement; 
now,  obviously,  for  this  to  be  done  sweetly,  the  spaces 
must  be  just  opposite  the  teeth  they  are  to  engage,  but 
should  they  not  thus  coincide,  much  grinding,  if  not  a 
broken  tooth,  may  result  in  a  clumsy  attempt  to  engage 
them.1 

Certain  precautions  should  be  taken  in  gear  chang- 
ing; for  example,  let  us  suppose  that  a  car  is  in  motion 
on  fairly  level  ground,  with,  say,  the  second  speed  gear 
in,  and  it  is  decided  to  change  up  to  the  third  speed, 
the  clutch  pedal  should  be  pressed  down  to  disengage 
the  clutch  and  allow  the  car  and  gear  to  continue  run- 
ning by  its  momentum,  then  with  a  pull  on  the  speed- 
lever  the  second  speed  wheels  are  disengaged,  and  an 

1This  gear  is  without  question  the  weak  link  in  the 
ordinary  car ;  that  it  is  a  barbarous  device,  although  a  con- 
venient one,  no  one  doubts,  and  its  ultimate  disuse  as  at 
present  arranged  can  be  sagely  predicted ;  although  they 
have  been  much  improved  by  beveling  the  tooth-faces  and 
increasing  the  pitch,  it  is  not  so  easy  to  indicate  upon  what 
lines  further  improvement  will  be  made.  There  are  already 
in  use  gears  that  can  be  easily  and  safely  changed,  the 
teeth  being  always  in  mesh,  the  tightening  of  a  band-brake 
bringing  a  particular  gear  into  use. 


74  MOTOES   AND   MOTORING 

attempt  made  to  put  into  mesh  the  teeth  of  the  third 
speed  wheels;  this  must  not  be  done  until  the  delicate 
sense  of  touch  has  conveyed  a  message  that  spaces  and 
teeth  coincide,  when  a  sharp  pull  or  jerk  will  engage  the 
wheels.  Now,  in  running  on  the  level  or  on  a  down 
grade,  this  operation  need  not  be  performed  hurriedly, 
indeed,  it  is  best  done  gently ;  but  in  putting  in  a  lower 
gear  up-hill,  not  a  moment  is  to  be  lost,  otherwise  the 
car  rapidly  slows,  and  if  time  is  lost  in  the  change,  the 
load  on  the  engine  suddenly  becomes  greater  when  the 
wheels  get  into  mesh,  often  requiring  a  little  relief  by 
slightly  disengaging  the  clutch,  allowing  a  little  slip- 
ping to  keep  the  engine  running  above  the  speed  at 
which  it  is  apt  to  stop.  There  is  always  the  danger, 
when  changing  speed  in  mounting  a  hill,  of  missing  the 
gear  altogether,  the  car  then  quickly  commencing  to 
run  back.  In  fact,  not  a  few  most  serious  accidents 
have  happened  in  this  way.  This  being  so,  we  will  care- 
fully indicate  what  should  be  done  in  negotiating  a  hill 
which  requires  a  change  of  gear.  Now,  as  soon  as  the 
car  gets  on  rising  ground,  the  accelerator  pedal  should 
be  pressed  to  allow  the  engine  to  exert  its  full  power 
on  the  gear  it  is  running  with  (which  will  probably  be 
its  highest  one),  then,  immediately  before  withdrawing 
the  clutch,  the  accelerator  pedal  is  released,1  and  on  the 
clutch  being  disengaged  the  speed-lever  is  promptly 
moved  over  to  the  required  notch,2  corresponding  to  the 
second  or  first  speed,  as  the  case  may  be,  and  when  this 
has  been  done  the  clutch  should  be  gently  put  in,  allow- 
ing slip  to  occur,  until  the  engine  takes  up  the  full 

lrThis  enables  the  governor  to  check  the  racing  of  the 
engine  during  the  moment  or  two  required  for  changing  the 
gear. 

2  A  deal  of  practice  is  required  to  do  this  with  certainty 
in  the  dark  or  without  looking.  The  expedient  of  connect- 
ing a  little  electric  light-up  with  the  gear-lever  and  the 
ordinary  four-volt  cells  used  for  ignition,  in  such  a  manner 
that  when  changing  gear  the  light  automatically  comes  into 
action,  and  immediately  goes  out  again  on  reaching  the 
proper  notch  or  gear,  was  introduced  some  year  or  two  ago, 
but  there  are  obvious  objections  to  its  use. 


MOTORS   AND   MOTORING  75 

load,  when  the  clutch  pedal  is  released  and  the  acceler- 
ator put  in  action.  Briefly,  a  gear  should  be  put  in  at 
the  moment  the  two  wheels  that  are  to  be  placed  in 
mesh  are  running  at  the  same  circumferential  speed. 

62.  Chain  Driving.— Although  during  the  past  year 
or  two  there  have  been  an  increasing  number  of  makers 
who  have  adopted  the  system  of  live-axle  and  gear 
transmission,  particularly  for  light  cars,  there  are  still 
a  great  many  who  pin  their  faith  to  chain  driving,  with 
its  rather  greater  simplicity  and  flexibility,  the  fact  of 
the  matter  being  that  either  system  is  in  a  way  a  com- 
promise, each  one  having  its  advantages  and  disadvan- 
tages. The  former  system,  perhaps,  on  the  whole,  is 
considered  by  engineers  the  best  mechanical-  arrange- 
ment; certainly  the  working  parts  are  better  protected, 
but  the  divided  axle  is  a  drawback,  and  should  it  acci- 
dentally get  bent,  it  means  a  big  job  to  get  it  right 
again,  or  even  true  enough  to  get  home  with,  whilst  a 
village  blacksmith  can  straighten  the  axle  of  a  chain- 
driven  car  with  certainty.  On  the  other  hand,  chains 
are  apt  to  break,  and  should  one  give  way  and  the  other 
continue  driving,  the  car  may  be  overturned  if  going  at 
a  high  speed;  of  course,  most  cars  carry  a  spare  chain, 
or  at  least  spare  links  that  can  be  fitted  on  the  road 
should  it  be  necessary.  After  chains  have  been  in  use 
some  time  they  stretch  and  become  loose,  and  have  to 
be  taken  up  either  by  lengthening  the  stretcher  bar1  or 
taking  out  a  link.  Chains  as  ordinarily  used  are  rarely 
run  at  their  highest  efficiency,2  as  it  is  quite  the  excep- 
tion to  see  any  attempt  made  to  properly  lubricate  them 
and  keep  the  dirt  off.  Users  of  the  common  bicycle 

1  The  stretcher  bar,  or  distance  rod,  is  used  as  an  adjust- 
able connection  between  the  axle  and  the  differential  shaft, 
the  distance  between  which  would  vary  considerably  with 
the  deflection  of  the  springs  were  this  rod  not  used. 

2  When   the  teeth   of   the   sprocket   wheels   are   correctly 
formed,  it  is  mostly  rolling  friction  which  occurs,  and  this 
accounts  for  the  liberties  that  can  be  taken  with  chains  in 
lubricating  them.     But  the  want  of  alignment,  that  is  so 
often  noticed,  even  in  the  best  cars,  means  loss  of  efficiency. 


?6  MOTORS   AtfD   MOTORING 

understand  the  advantage  of  using  a  gear-case  with  the 
chain  running  in  oil;  it  is  true  that  there  are  difficul- 
ties in  fitting  cars  this  way,  but  it  is  not  easy  to  under- 
stand why  some  protection  has  not  heen  more  generally 
given  to  car  chains;  so,  as  things  are,  periodical  atten- 
tion must  be  given  to — 

63.  Cleaning    and    Lubricating    the    Chains. — They 
should  be  first  thoroughly  cleaned  with  paraffin,  then 
soaked  in  melted  refined1  Eussian  tallow,  care  being 
taken  not  to  allow  the  tallow  to  become  hotter  than  is 
necessary  to  keep  it  in  the  liquid  state,  as  the  temper  of 
the  chain  may  be  affected.     After  the  chain  has  been 
moved  about  in  the  melted  grease  to  allow  it,  the  grease, 
to  come  in  contact  with  the  surfaces  of  the  rollers  and 
rivets,  the  chain  should  be  hung  up  and  the  lubricant 
allowed  to  drain  into  the  shallow  tin  used  for  the  pur- 
pose.    Plumbago  and  tallow  make  an  excellent  lubri- 
cant, but  it  is  very  difficult  to  effectually  apply,  as  the 
plumbago  sinks  to  the  bottom  of  the  vessel  as  soon  as 
the  tallow  becomes  melted. 

64.  Brakes. — Every  car  must  by  law  be  fitted  with  at 
least  two  brakes,  but  most  cars  of  any  importance  have 
three,  one  at  each  driving  wheel,  and  one  somewhere  on 
the  primary  shaft,  and  it  is  almost  the  universal  prac- 
tice to  make  one  of  these  (generally  the  latter)  a  foot- 
brake,  arranged  to  withdraw  the  clutch  as  the  brake  is 
applied,  and  in  some  cases  to  also  throttle  the  mixture. 
The  second  brake  (or  brakes)  is  usually  worked  by  a 
side-hand  lever;  this  brake  should  on  no  account  be 
made  to  disengage  the  clutch  when  it  is  used,  as  the 
engine  itself  can  be  made  to  act  in  cases  of  emergency 
as  an  auxiliary  brake,2  if  the  clutch  remains  engaged. 

^he  tallow  can  be  refined  by  placing  it  in  a  pail  of  boil- 
ing water,  stirring  till  it  is  all  melted,  when  the  foreign 
matter  will  be  precipitated,  and  a  solid  block  of  clean  tallow 
form  on  the  surface  when  cooled. 

2  A  car  sometimes  stops  on  a  hill,  which  for  some  reason 
or  other  it  can't  climb ;  the  tendency  then  is  for  the  weight 
of  the  car  to  gradually  make  the  engine  run  backwards  and 
allow  the  vehicle  to  descend  the  hill ;  of  course,  as  soon  as 


MOTORS   AND   MOTORING  77 

Most  cars  are  fitted  with  band  brakes  on  the  driving 
wheels,  as  shown  in  Fig.  18,  but  several  makers  have 
abandoned  these  in  favor  of  some  form  of  expanding 
brake  acting  on  the  inner  surface  of  a  ring  or  annular 
flange.1  It  is  imperatively  necessary  that  all  car  brakes 
should  be  so  constructed  that  they  are  equally  effective 
whether  the  car  be  moving  forward  or  backward,  for 
upon  the  perfect  working  of  the  brakes  depends  the 
safety  of  the  car  and  its  occupants. 

The  conditions  which  a  good  brake  should  satisfy 
are  the  following: — 

(1)  The  maximum  force  required  to  work  it  by  foot 
or  hand  to  be  one  that  can  be  applied  without  undue 
exertion. 

this  happens  the  sprag  should  be  lowered,  and  if  this  holds 
before  the  car  gets  on  too  much  way  all  is  well,  but  it  is 
easy  to  see  that  so  long  as  the  clutch  is  in,  the  friction  and 
compression  in  the  cylinder  retard  the  motion  of  the  car, 
and  the  withdrawal  of  the  clutch  cuts  out  this  resistance, 
often  with  a  resulting  increase  in  the  velocity  of  the  car 
before  the  hand  or  emergency  brake  can  be  put  on,  although 
the  foot-brake  be  at  once  applied.  This  must  not  be  con- 
fused with  what  is  done  when  a  car  is  running  forward,  and 
its  speed  is  suddenly  arrested  by  an  application  of  the 
brake;  the  foot-brake  is  then  used,  the  clutch  being  with- 
drawn by  the  same  pedal,  instantly  disconnects  the  clutch 
shaft  from  the  engine,  which  then  runs  unloaded.  This 
arrangement  gives  the  driver  wonderful  control  over  the 
car,  as  its  stoppage  is  not  dependent  upon  his  power  to 
suddenly  bring  up  his  engine  to  a  standstill.  Of  course  the 
beauty  of  the  system  is  that  when  the  car  is  temporarily 
stopped  the  engine  continues  running,  so  that  a  restart  can 
be  instantly  made  by  letting  in  the  clutch.  Indeed,  it  is 
not  easy  for  those  who  have  not  driven  a  car  to  understand 
what  perfect  control  the  driver  has  over  it;  for  instance, 
it  was  proved  by  brake  tests  carried  out  by  the  Automobile 
Club  of  America  that  over  70  feet  were  required  to  pull  up 
a  four-in-hand  coach  running  at  about  sixteen  miles  per 
hour,  whilst  a  Panhard  car  running  at  the  same  speed  was 
brought  to  a  standstill  in  25  ft.  4  ins. 

*In  chain  drives  this  is  a  particular  form  of  sprocket 
ring.  With  such  arrangements  it  is  practicable  to  better 
protect  the  rubbing  surfaces  from  oil  and  dirt,  which  reduce 
their  efficiency,  and  increase  the  wear  and  tear,  but  they  are 
less  get-at-able  and  more  difficult  to  examine. 


78  MOTOKS   AND   MOTORING 

(2)  The  movement  of  pedal  or  lever  to  apply  the  full 
power  of  the  brake  not  to  be  more  than  can  be  conven- 
iently made  by  the  driver. 

(3)  The  bands  or  blocks  to  be  suspended  in  such  a 
way  that  they  are  only  in  contact  with  the  brake,  pulley, 
ring,  or  flange  when  the  brake  is  applied,1  being  at 
least  a  £  inch  clear  all  round  at  other  times. 

(4)  Absence  of  fierceness  in  the  action  of  the  brake.2 
No  part  of  the  car  requires  more  intelligent  care  in 

its  manipulation  than  the  brake,  if  it  is  to  be  worked 
when  necessary  for  all  it  is  worth  without  abnormal 
injury  to  the  tires.  It  works  with  the  greatest  effect 
when  the  tires,  due  to  its  application,  are  just  on  the 
point  of  skidding ; 3  for  when  skidding  occurs  the  rub- 
ber is  eroded,  and  the  friction  between  ground  and  tire 
is  very  much  decreased  instead  of  becoming  greater,  as 
most  people  would  expect. 

65.  Ball  Bearings. — Headers  who  are  old  enough  to 
have  ridden  a  bicycle  before  the  introduction  of  ball 
bearings,  and  have  had  riding  experience  with  both 
kinds,  will  be  in  a  position  to  estimate  the  marked  ad- 
vantage ball  bearings  have  over  ordinary  ones,  so  far 
as  frictional  resistance  is  concerned,  and  with  cars  this 
difference  is  just  as  striking ;  indeed,  a  few  things  appear 
to  be  more  perfect  than  the  running  of  car  wheels, 
mounted  on  well-adjusted  ball  bearings;  but  the  ball 
bearing  has  an  advantage  over  the  plain  bearing,  only 
so  long  as  the  hard  steel  balls  remain  in  perfect  form, 

*A  common  source  of  trouble  in  the  way  of  noise,  wear, 
and  loss  of  power,  is  the  rubbing  of  brake-bands,  due  to 
want  of  adjustment  or  faulty  construction. 

2  The  true  function  of  a  brake  is  to  retard  a  wheel,  not 
lock  it;  should  it  do  the  latter,  then  the  tires  must  skid, 
and  the  most  expensive  part  of  the  car  (the  tires)  is  seri- 
ously worn  and  injured,  instead  of  a  little  wear  occurring  in 
the  strap  and  ring,  which  can  be  easily  replaced. 

3  The  old-fashioned  spoon-type  brake,  acting  directly  upon 
the  tread  of  the  tire,  was  abandoned  on  account  of  its  low 
efficiency  and  the  manner  in  which  it  used  to  wear  out  the 
cover  of  the  tire. 


MOTOES   AND   MOTOKING  79 

and  no  longer,  for  should  a  ball  break,  there  is  always 
the  probability  that  a  portion  or  portions  of  the  ball 
may  get  across  or  become  jammed  in  the  ball  races, 
scoring  them  or  the  axle,  or  both,  whilst  in  some  cases 
the  axles  have  been  held  tight  and  fractured  by  the  sud- 
den strain.  Frequently  ball  bearings  are  allowed  to 
run  far  too  long  without  attention  and  lubrication,  with 
the  result  that  when  they  are  inspected  some  of  the 
balls  are  found  to  have  worn  sharp  or  rough,  and  per- 
haps to  have  grooved  the  cups  and  cones  of  the  races 
upon  which  they  run.  Eenewing  the  latter  is,  of  course, 
an  expensive  matter;  it  is  much  more  economical  to 
replace  the  whole  of  the  balls  as  soon  as  there  is  any 
appreciable  sign  of  wear,  even  if  a  single  ball  is  faulty, 
as  a  new  one  would  have  to  be  exactly  the  same  size  as 
the  others,  and  few  people  are  capable  of  gauging  the 
size  with  sufficient  accuracy.  Obviously,  if  one  of  the 
balls  happens  to  be  a  shade  larger  than  the  others,  it 
will,  each  time  it  reaches  the  bottom  of  its  race,  support 
the  whole  weight,  and  sooner  or  later  will  break.  To 
be  on  the  safe  side,  these  bearings  should  be  examined 
every  1000  miles,  and  the  balls  renewed  about  every 
5000  miles.  In  placing  balls  in  their  races,  care  must 
be  taken  not  to  get  them  too  crowded;  indeed,  if  there 
is  any  doubt  as  to  whether  a  certain  number  can  be 
got  in,  it  is  better  to  put  in  one  less,  and  be  sure  that 
they  are  not  jammed  together  when  the  cone  is  screwed 
up. 

If  no  lubricator  is  provided  for  the  hub  barrel,  the 
axle  cap  should  be  taken  off,  filled  with  grease,  and 
screwed  right  home,  every  few  hundred  miles;  this  will 
force  the  grease  into  both  races,  and  keep  things  right. 
Ball  bearings  require  careful  adjustment  to  keep  them 
in  order,  the  adjusting  cone  being  tightened  till  all 
side  shake  has  been  taken  up,  and  the  wheel  is  solid  on 
its  bearing ;  at  the  same  time,  it  must  run  with  the  most 
absolute  freedom.  Of  course  this  adjustment  can  only 
be  made  when  the  wheel  is  jacked  up  clear  of  the 
ground;  and  it  should  be  remembered  that  the  adjust- 


80  MOTOES   AND   MOTOKING 

ing  nuts,  upon  the  right-hand  side  wheels,  are  made 
with  a  right-hand  thread,  whilst  those  on  the  left-hand 
side  of  the  car  are  fitted  with  a  left-hand  threaded  ad- 
justing nut.  The  reason  of  this  arrangement  should 
he  obvious,  for  should  the  lock-nut  by  any  means  work 
loose,  the  tendency  of  the  adjusting  nuts  on  both  sides, 
due  to  the  motion  of  the  wheels  in  contact  with  them, 
is  to  tighten  themselves  upon  the  axle. 

66.  The  Tires. — We  may  now  give  some  attention  to 
the  vexed  question  of  the  tires.  Should  they  be  solid 
or  pneumatic?  is  a  question,  like  so  many  others  relat- 
ing to  motor  vehicles,  that  cannot  be  answered  definitely 
without  qualifications.  The  principal  factors  which 
have  to  be  considered  in  making  a  decision,  being  the 
maximum  speed  the  car  is  to  run  at,  the  character  of 
the  roads  the  car  is  to  run  on  (i.e.,  is  the  car  required 
for  town  or  touring  purposes?),  the  weight  of  the 
vehicle,  the  size  and  flexibility  of  its  springs,  comfort, 
and  reliability.  Those  who  have  had  long  experience 
with  pneumatic  tires,  particularly  if  they  have  run 
them  after  they  have  given  unmistakable  signs  of  de- 
preciation, would  willingly  sacrifice  a  little  comfort  if 
they  could  secure  immunity  from  tire  troubles  by  adopt- 
ing solids ;  but  even  with  solid  rubber  tires  we  have  not 
perfect  reliability,  as,  under  exceptional  circumstances, 
the  fixing  cement  is  apt  to  get  heated  enough  by  road 
friction  to  melt,  and  allow  the  tires  to  creep  slightly  on 
the  rims,  the  cement  accumulating  at  some  parts  of  the 
latter  to  an  extent  sufficient  to  gradually  force  the  tires 
from  them,  causing,  at  the  same  time,  an  abrasive  action 
between  the  tires  and  rims,  the  tendency  of  the  tires  to 
leave  the  rims  being  increased  by  the  centrifugal  force, 
when  running  at  a  high  speed.  Moreover,  the  use  of 
solid  tires  necessitates  the  use  of  springs  of  greater 
flexibility;  and  provision  must  be  made  for  a  greater 
vertical  movement  between  the  frame  and  axles,  which 
means,  in  most  chain-driven  cars,  a  varying  tightness 
of  the  chains,  and  in  gear-driven  ones,  a  greater  varia- 
tion in  the  uniformity  of  transmission,  due  to  the 


MOTORS   AND   MOTOEING  81 

greater  obliquity1  of  the  propeller  shaft.  But,  notwith- 
standing these  drawbacks,  there  are  many  who  pin  their 
faith  to  solid  tires,  particularly  for  town  use,  as  the 
roads  are  generally  fairly  good,  and  the  speed  rarely 
exceeds  some  sixteen  miles  per  hour.  An  additional 
advantage  may  be  mentioned,  and  that  is,  there  is  not 
quite  so  much  skidding  with  solid  tires  .as  with  pneu- 
matic ones.  So,  for  those  who  never  wish  to  exceed  a 
most  moderate  speed  with  the  minimum  of  tire  troubles, 
particularly  if  they  are  not  too  exacting  where  their 
ease  in  riding  is  concerned,  solid  tires,  fitted  to  a  light 
but  strong  car,  built  for  their  use,  would  be  a  wise 
selection.  On  the  other  hand,  it  is  not  easy  for  anyone 
who  has  once  enjoyed  the  luxury  of  driving  in  a  good 
car,  suitably  fitted  with  pneumatic  tires,  to  revert  to 
solid  ones;  indeed,  the  temptation  to  run  the  risk  of 
trouble,  and  take  his  chance,  seems  almost  irresistible; 
but  we  must  be  careful  not  to  in  any  way  exaggerate 
the  disadvantages  of  pneumatic  tires,  for,  in  addition 
to  their  wonderful  resilience,  they  run,  when  properly 
inflated,  with  less  resistance  than  solids,  and  if  they 
are,  in  the  first  instance,  of  suitable  size  2  and  of  good 
quality  (as  they  would  be  if  supplied  by  any  of  the 
famous  makers),  and  proper  care  is  taken  of  them  when 
in  use,3  also  when  they  are  stored  or  on  the  wheels  of 
a  laid-up  car,4  they  may  be  expected  to  run  some  3000 

1When  the  universal  joints  of  the  propeller  shaft  come 
into  use,  they  cause,  or  tend  to  cause,  a  difference  in  the 
uniformity  of  running  of  the  clutch  shaft  and  driving  wheel 
axle ;  that  is  to  say,  if  the  former  was  running  with  uni- 
formity, the  latter  would  be  moving  with  slight  variations 
for  each  turn  of  the  propeller  shaft. 

2  There  is   a  tendency  on  the  part  of  many  makers  to 
keep  down  the  size  and  weight  of  pneumatic  tires  to  such 
an  extent  that,  from  the  first,  they  are  overloaded.     If  in 
doubt  as  to  the  size,  it  is  always  wiser  to  err  on  the  right 
side,  and  use  a  tire  of  ample  size  and  strength. 

3  Refer  to  footnote  on  Brakes,  page  78. 

4  Rubber  commences  to  deteriorate  if  exposed  to  a  strong 
light  or  high  temperatures,  or  if  brought  in  contact  with 
rust,  grease,  or  most  of  the  acids.     So  spare  tires  should  be 
protected  from  the  light,  and  stored  in  a  place  the  temper- 


83  MOTOES   AND   MOTOKING 

or  4000  miles  before  they  require  replacing  (solids,  if 
of  the  best  make,  run  over  twice  the  distance  and  cost 
about  half  as  much) ;  of  course,  the  first  serious  trouble 
may  be  due  to  the  inner  tubes  commencing  to  perish ;  if 
so,  these  can  be  easily  and  comparatively  inexpensively 
replaced.  Every  driver  of  a  touring  car  should  be  able 
to  repair  a  puncture,  and  to  lace  a  leather  sleeve  gaiter 
or  shoe  over  the  outer  cover  of  a  tire  and  around  the 
felloe  of  the  wheel,  should  a  cover  burst  on  the  road. 
Needless  to  say,  tires  which  have  suffered  from  bursts 
should  be  returned  to  their  makers  at  the  earliest  op- 
portunity, so  that  the  cover  may  be  properly  repaired 
and  vulcanized.  It  is  a  great  mistake  to  run  a  car  with 
soft  tires,  as  many  are  tempted  to  do,  either  by  the  easy 
running,  or  to  avoid  the  trouble  of  pumping  up;  it 
means  excessive  wear  and  rapid  depreciation.  They 
should  be  inflated  until  they  are  just  on  the  point  of 
bulging  at  the  tread  under  the  full  load ;  this  is  a  better 
guide  than  a  pressure  gauge,  as  gauges  are  not  always 
to  be  relied  upon,  and  after  the  covers  have  become 
worn  a  given  pressure1  has  a  different  effect  upon  them. 
When  cars  are  garaged  or  stabled  for  several  weeks  they 
should  be  jacked  up,  so  that  the  wheels  are  clear  of  the 
ground,  and  the  fabric  liners  of  the  tires  are  not  con- 
tinuously under  stress;  if  this  is  done,  it  is  not  neces- 
sary to  deflate  the  tires.  An  occasional  wipe  with  a 
damp  sponge  will  keep  them  in  condition  if  they  are 
not  exposed  to  heat  and  sunlight,  as  previously  ex- 

ature  of  which  does  not  exceed  some  75°F.  Although  tires 
which  have  been  in  use  are  not  so  much  affected  by  heat 
and  light  as  new  ones,  care  should  be  taken  to  protect  them 
if  the  car  is  laid-up  for  any  time,  and  to  remember  that 
they  can  only  be  kept  in  good  condition  by  washing  the  mud 
and  dirt  off  them  after  every  run.  In  removing  the  cover 
from  the  rim  of  the  wheel,  the  paint  is  sure  to  be  more  or 
less  injured,  and  if  such  exposed  parts  are  not  painted 
again,  when  an  opportunity  occurs,  with  some  air-drying 
enamel,  rust  will  accumulate  and  injure  the  tire. 

1  The  pressure  per  square  inch  varies  from  about  35  in  the 
tires  of  the  lightest  cars  to  about  110  in  those  of  the 
heaviest. 


MOTOES   AND   MOTOKING  83 

plained.  The  covers,  inner  tubes,  and  rims  require 
periodical  examination  for  any  of  the  defects  that  have 
been  referred  to.  Abnormal  wear  on  the  front  tires 
always  occurs  when  the  front  wheels  are  not  in  align- 
ment with  the  rear  ones,  that  is  to  say,  when  their  hori- 
zontal diameters  are  not  parallel  for  the  position  they 
are  in  when  the  car  is  running  forward  in  a  straight 
line.  Any  want  of  such  alignment  means  a  combined 
rolling  and  sliding,  or  grinding  action,  as  the  wheel 
passes  over  the  ground.  A  similar  action  occurs  when, 
through  some  defect  in  the  design  of  the  steering  gear, 
or  through  some  straining  action,  the  front  wheels  do 
not  come  to  the  proper  angles  which  they  should  make 
with  the  front  axle  when  turning  a  corner.  These  an- 
gles are  only  equal  when  the  car  is  running  in  a  straight 
line,  but  when  turning  a  corner  the  near-side  wheel 
should  be  running  in  a  sharper  curve  than  the  off-side 
one  for  correct  running,  therefore  the  gear  must  guide 
it  into  a  position,  making  a  smaller  angle  with  the  axle 
than  the  off-side  one  does.  A  very  simple  and  familiar 
expedient  enables  the  designer  to  arrange  his  steering 
gear  to  do  this;  but  it  is  often  in  the  actual  construc- 
tion of  the  car  that  such  adjustments  are  apt  to  be 
made  without  sufficient  care,  although,  of  course,  in  the 
works  of  the  best  makers  both  at  home  and  abroad,  so 
great  is  the  care  taken  that  such  parts  are  little  short 
of  perfect  when  the  car  is  turned  out. 

67.  Road  Wheels. — The  designer  cannot  give  too 
much  attention  to  road  wheels.  These  are  made  of 
either  oak  or  metal,  the  former,  known  as  the  artillery 
wheels,  being  now  almost  exclusively  used,  as  they  wear 
very  well,  have  a  better  appearance  than  the  others,  and 
are  more  easily  cleaned.  But  it  can  be  proved  that 
motor-car  wheels,  to  have  a  margin  of  safety  equal  to 
that  which  the  wheels  of  horse-drawn  vehicles  have, 
must  be  many  times  stronger;  in  fact,  they  cannot  be 
too  strong  for  our  purpose,  as  the  very  lives  of  motor- 
ists depend  upon  the  wheels  being  able  to  safely  with- 
stand the  tremendous  strain  set  up  by  turning  a  corner 


84  MOTORS   AND   MOTORING 

at  high  speed,  or  by  any  obstruction  that  tends  to  dish 
them  at  a  time  when  they  are  transmitting  consider- 
able power.  This  is  one  of  the  reasons  why  motor-ear 
wheels  are  kept  down  in  size,  although  it  is  common 
knowledge  that  the  larger  the  wheels,  the  less  power 
required  to  drive  a  given  carriage.  There  are  other 
reasons  why  large  wheels  are  not  used,  for  they  greatly 
increase  the  cost  of  both  wheels  and  tires,  and  make 
access  to  the  seats  more  difficult,  whilst  they  raise  the 
center  of  gravity  of  the  vehicle,  reducing  its  stability 
in  turning  corners.  On  the '  other  hand  they  run 
smoother,  lick  up  less  dust,  and  more  easily  surmount 
any  obstacle.  So  again  we  have  a  compromise. 

68.  Balanced  Engines. — Perfect  smoothness  of  run- 
ning can  only  be  secured  by  fitting  the  car  with  a  well- 
balanced  engine.  This  would  appear  to  be  a  very  easy 
matter,  as  almost  every  maker  of  a  gasolene  engine  claims 
that  it  .is  perfectly  balanced,  whether  it  be  a  single- 
cylinder  one,  a  two-cylinder,  three-cylinder,  or  whatever 
number  of  cylinders  it  may  have.  In  fact,  when  bal- 
ancing is  thus  referred  to,  a  very  loose  interpretation 
of  the  word  is,  or  should  be,  intended.  The  balancing 
of  a  reciprocating  engine  might  appear  at  first  to  rep- 
resent the  very  simple  problem  which  in  the  single-cyl- 
inder engine  is  usually  solved  by  forming  weights  on 
the  crank  arms  (as  shown  in  Fig.  1)  to  balance  the  re- 
volving and  reciprocating  masses;  but  after  this  has 
been  done  (without  going  into  refinements  that  would 
be  of  interest  to  an  engineering  student,  but  could 
scarcely  be  followed  by  the  general  reader),  there  re- 
main in  the  vertical  engine  unbalanced  inertia  forces, 
caused  by  the  moving  parts,  which  produce  a  vertical 
hammering  action.  Now,  if  instead  of  a  single-cylinder 
engine  we  consider  a  two-cylinder  engine,  with  cranks 
at  180°,  and  reciprocating  masses  equal,  there  are  cer- 
tain forces  and  couples  which  cannot  be  balanced,  and 
they  result  in  a  tilting  effect  which  tends  to  rock  the 
engine  in  a  fore  and  aft  direction,  and  cause  serious 
vibration  But  with  three  cylinders,  with  equal  masses 


MOTORS   AND   MOTORING  85 

at  the  crank  radius,  and  the  cranks  at  120°,  the  engine 
can  be  arranged  to  run  with  a  more  uniform  turning 
action,  and  with  the  vertical  hammering  action  practi- 
cally eliminated,  a  distinct  advantage  over  the  two- 
cylinder  one;  but,  so  far  as  the  rocking  action  (due  to 
certain  unbalanced  couples1)  is  concerned,  this  engine 
has  little  or  no  advantage  over  the  two-cylinder  one  of 
the  same  power.  Now,  by  adding  another  cylinder,  we 
get  a  four-cylinder  engine,  which  gives  the  designer  a 
much  better  chance  of  approximating  to  a  true  balance, 
for  with  cranks  at  180°  apart,  the  usual  arrangement  in 
motor-car  engines,  a  perfect  fore  and  aft  balance  is  pos- 
sible; but  the  vertical  hammering  effect  can  only  be 
imperfectly  dealt  with,  in  fact  with  no  more  success 
than  in  a  two-cylinder  engine.  Notwithstanding  this, 
it  cannot  be  denied  that  four-cylinder  engines  are  pro- 
duced which,  when  run  at  the  speed  they  were  designed 
to  work  at,  are  hard  to  beat  for  smoothness  of  running. 
But  those  who  have  paid  attention  to  these  matters  will 
know  that  to  attain  the  highest  possible  condition  of 
balance  in  an  engine,  five  or  six  cylinders  are  necessary. 
Even  with  the  required  number  of  cylinders,  the  exer- 
cise of  consummate  skill  in  designing  the  balancing  sys- 
tem is  necessary  to  produce  an  engine  that  will  run 
without  vibration;  indeed,  a  wealth  of  mechanical 
genius  has  been  lavished  on  the  evolution,  of  the  highest 
form  of  gasolene  engine,  and  some  elegant  expedients 
have  been  devised  in  solving  the  balancing  problems.2 
So  it  will  be  seen  that  the  balancing  of  engines  is  a 
subject  on  which  the  man  in  the  street  is  not  likely  to 
be  very  well  informed,  in  fact,  is  most  likely  to  be  easily 
misled. 

69.  Lubrication. — No  car  can  be  efficiently  run  with- 
out trouble  occurring,  or  even  a  breakdown,  unless  it 
has  been  constructed  in  such  a  way  that  all  the  wearing 

1  To  keep  down  the  disturbing  effect  of  these  couples  (the 
primary  and  secondary),  the  cylinders  should  be  placed  as 
near  together  as  practicable. 

"  One  of  the  most  interesting  of  which  is  to  be  found  in 
the  Lanchester  engine. 


86  MOTORS   AND   MOTORING 

parts  can  be  easily  and  properly  lubricated.  No  driver 
can  hope  to  run  his  car  without  trouble,  unless  he  has 
made  a  business  of  mastering  the  arrangements  made 
for  lubricating  its  various  working  parts  and  under- 
standing the  maker's  instructions  relating  to  them;  in- 
deed, he  should  never  take  a  car  out  without  first  being 
sure  that  everything  connected  with  its  lubrication  is 
in  order,  for,  obviously,  it  is  too  late  to  commence  to 
pay  attention  to  such  matters  when  he  hears  ominous 
sounds  emanating  from  bearings  or  rubbing  surfaces, 
that  plainly  tell  him  that  they  are  on  the  point  of  gall- 
ing or  seizing  for  want  of  proper  lubrication.  New 
engines  in  particular  require  plenty  of  the  best  oil,  as 
they  are  more  apt  to  give  trouble  until  all  their  bearings 
have  rubbed  down  to  their  work.  Much  ingenuity  has 
been  displayed  in  designing  the  innumerable  forms  of 
lubricators  and  lubricating  devices  in  common  use  on 
cars  for  securing  a  regular  feed  to  the  various  bearing 
surfaces,  with  the  result  that  they  not  only  vary  with 
the  car,  but  with  different  parts  of  the  same  car.  The 
most  perfect  way  to  lubricate  a  bearing  is  to  immerse 
it  in  an  oil-bath,  and  the  more  nearly  this  ideal  arrange- 
ment (which  is  rarely  practicable)  is  approached,  the 
more  satisfactory  the  result;  but  a  close  approximation 
to  this  is  to  be  found  in  the  admirable  forced  or  circu- 
lating-pump lubrication  employed  on  the  Maudslay, 
Mercedes,  Wilson-Pilcher,  and  other  cars.  In  this  sys- 
tem the  oil  is  forced  through  the  bearings,1  from  which 
it  is  drained,  filtered,  and  re-used,  with  the  great  ad- 
vantage that  it  only  circulates  whilst  the  engine  runs. 
Ring  lubrication  also  gives  a  good  approximation  to 
it,2  and  in  many  of  the  best-known  cars  the  crank-shaft 

1A  fundamental  condition  for  efficient  lubrication  is  that 
the  oil  must  be  fed  into  the  bearing  at  the  slack  side. 

2  The  bearings  are  made  in  such  a  way  that  a  collar  or 
ring  on  the  shaft,  just  fitting  it  and  revolving  with  it,  dips 
into  the  oil  in  the  well,  there  being  a  break  in  the  bearing 
at  its  center  to  allow  of  this.  Of  course,  with  this  arrange- 
ment the  oil  is  being  constantly  lifted  from  the  well  by  the 
ring  as  it  revolves,  flowing  down  from  its  highest  position 
into  the  bearing,  and  back  into  the  well  again. 


MOTORS   AND   MOTORING  87 

bearings  are  fitted  with  these  useful  devices,  each  bear- 
ing having  a  lubricating  well,  which  is  from  time  to 
time  supplied  with  oil  from  the  oil  sights  on  the  dash- 
board, or  from  an  oil  reservoir  by  a  hand-pump,  as  in 
the  Decauville  car. 

The  important  crank-pin  bearings  are  generally  lubri- 
cated by  partly  filling  the  crank-chamber  with  a  cylin- 
der *  oil  to  such  a  height  as  to  allow  the  ends  of  the  con- 
necting rods  to  dip  a  little  into  it,  and  in  so  doing  lubri- 
cate the  crank-pins  each  time  they  come  into  their  lowest 
position;  this  causes  a  deal  of  splashing,  which  is  inva- 
riably utilized  to  lubricate  the  cylinder  by  wetting  the 
bottom  of  the  piston  2  and  the  wall  of  the  lower  part  of 
the  cylinder.  After  a  time  this  oil  becomes  vitiated 
and  requires  changing,3  and  it  is  as  well  to  do  this 
about  every  50  or  60  to  100  miles,  according  to  the  size 
of  the  engine,  the  smaller  ones  requiring  most  frequent 
attention.  The  lubrication  of  most  of  the  other  impor- 
tant bearings  is  pretty  generally  performed  by  a  sight- 

lrrhe  practice  of  supplying  oil  to  the  crank-chamber  in 
doses,  and  trusting  to  its  being  splashed  over  the  gudgeon- 
pin  and  cylinder  wall,  is  the  one  generally  adopted,  and 
although  rather  haphazard,  it  seems  to  work  well,  but  as 
the  oil  has  to  lubricate  the  cylinder,  it  must  be  of  good 
quality,  suitable  for  cylinder  use.  Sometimes  an  additional 
drip  lubricator  feeds  oil  to  the  cylinder  wall  near  the  lowest 
position  of  the  piston,  but  unless  this  is  forced  by  some 
means,  a  thin  oil  has  to  be  used,  and  then,  for  obvious 
reasons,  it  is  of  doubtful  utility. 

*A  grooved  ring  is  sometimes  fitted  into  the  bottom  of 
the  cylinder,  so  that  the  oil  may  accumulate  in  the  groove, 
and  the  ring  end  of  the  bottom  of  the  piston  dip  into  it, 
smearing  the  cylinder  wall  with  oil  from  it  each  up-stroke. 

8  This  is  done  by  unscrewing  a  plug  at  the  bottom  of  the 
crank-chamber  and  allowing  the  oil  to  escape,  the  fresh  oil 
being  poured  into  the  chamber  (till  it  is  about  a  third  full) 
through  a  similar  hole  in  its  upper  part.  It  is  necessary 
to  occasionally  wash  out  the  chamber  with  paraffin  to  keep 
it  clean ;  and  to  prevent  an  excess  of  oil  accumulating  in 
the  chamber,  an  overflow  pipe  is  sometimes  fitted,  as, 
should  the  chamber  become  too  full,  too  much  oil  is  apt  to 
find  its  way  into  the  cylinder  and  lodge  between  the  points 
of  the  sparking  plug,  impairing  ignition. 


88  MOTORS   AND   MOTORING 

feed  lubricator,  which  should  be  regulated  not  so  much 
for  a  large  supply,  but  for  a  certain  and  continuous 
flow.  In  some  of  these  lubricators  all  the  tubes  are 
governed  by  one  tap,  which  is  the  only  one  that  requires 
opening  and  shutting,  the  others  having  been  once  ad- 
justed for  the  feed  required  in  each  case.  Needless  to 
say,  the  efficiency  of  this  system  largely  depends  upon 
the  tubes  being  kept  clean  and  free  from  obstructions. 
In  many  cars  lubrication  is  effected  by  an  automatic 
positive  feed  arrangement,  the  oil  distribution  com- 
mencing automatically  when  the  engine  is  started,  and 
ceasing  when  stopped,  no  turning  on  or  off  being  re- 
quired. An  interesting  example  of  this  type  is  fitted 
to  the  Lanchester  cars,  where  the  bottom  of  the  oil- 
tank  is  made  to  fit  a  spindle  running  longitudinally 
through  it,  so  that  the  upper  part  of  the  spindle  is  in 
communication  with  the  bulk  of  the  oil,  whilst  the 
lower  half  is  opposed  to  a  series  of  outlets  which  com- 
municate with  the  various  parts  to  be  lubricated.  The 
spindle,  which  is  rotated  by  a  worm-gear  from  the  half- 
speed  shaft,  has  a  series  of  pockets  or  depressions  cut 
in  it — one  opposite  each  outlet — so  that  in  rotating 
these  pockets  first  fill  with  oil  from  the  tank,  and  after- 
wards discharge  their  contents  into  the  various  pas- 
sages for  distribution. 

In  some  systems  of  lubrication  provision  is  made  to 
prevent  the  flow  of  oil  being  affected  by  cold  weather. 
Thus  in  the  fine  Crossley  car,  the  oil  is  forced  from  the 
main  tank  by  exhaust  pressure1  to  water-heated  sights 
on  the  front  of  the  dashboard,  the  oil  being  thus  kept 
warm,  and  its  flow  constant  at  all  temperatures  of  the 
atmosphere. 

Change-speed  gears  generally  run  in  thick  oil,2  the 

1  In  the  James  and  Browne  lubricator,  oil  is  supplied  from 
the  tank  through  sight-feed  glasses,  by  pressure  derived 
from  an  induced  vacuum  on  the  crank-chamber. 

1  Grease  is  sometimes  used  for  this  purpose,  but  if  this 
be  too  viscous  to  flow,  the  wheels  cut  for  themselves  races 
in  the  body  of  the  stuff  in  which  they  revolve,  niore  or  less 


MOTOES   AND   MOTOEING  89 

gear-case  being  occasionally  partly  filled  with  it,  after 
drawing  off  the  old  and  dirty  oil.  The  more  out  of 
sight  a  bearing  may  be,  or  the  smaller  the  amount  of 
motion  in  it,  the  more  likely  it  is  to  be  neglected,  as, 
even  if  it  works  dry,  the  feeble  squeaking  noise  it  makes 
is  often  unheard.  This  particularly  applies  to  parts 
which  are  ordinarily  lubricated  with  the  common  oil- 
can, such  as  the  regulating  mechanism,  the  valve-rod 
thrust  bearing,  lever  hinges  and  the  steering  gear,  which 
require  regular  attention.  Even  the  leaves  of  the  springs 
require  occasional  greasing,1  or  they  will  grind  on  one 
another  and  become  noisy.  On  many  cars  Stauffer 
grease-boxes  are  fitted  to  some  of  the  minor  parts ;  these 
require  screwing  up  about  an  eighth  of  a  turn  for  every 
60  to  100  miles  run.  The  advantage  of  this  arrange- 
ment is,  that  should  a  bearing  run  hot,  the  grease  melts 
and  flows  over  the  journal.2  Beginners  usually  err  on 
the  side  of  using  far  too  much  oil,3  but  this  is  a  fault 
on  the  right  side,  and  with  any  given  car  only  experi- 
ence with  close  observation  will  teach  its  driver  how  to 
judiciously  use  an  expensive  material,  and  keep  his 
mount  in  the  pink  of  running  condition.  After  a  time, 
the  temptation  with  some  to  take  liberties  with  the  car 
is  great,  and  they  may  even  run  it  a  whole  day  without 
attending  to  its  lubrication,  but  such  a  liberty  as  this 
cannot  be  taken  every  day  without  at  least  serious  de- 
preciation occurring. 

70.  Lubricating  Oils  for  the  cylinders  must  be  of  a 

from  contact  with  the  lubricant.  The  same  thing  occurs 
with  oils  that  solidify  at  temperatures  that  can  hardly  be 
considered  low.  In  the  best  practice,  the  bearings  in  the 
gear-case  are  independently  lubricated,  as  the  oil  in  the 
case  becomes  charged  with  metal  dust  and  small  chips 
from  the  wheels. 

1This  is  done  by  jacking  up  the  frame  till  the  leaves  of 
the  spring  can  be  separated  a  little  by  a  screwdriver,  when 
grease  is  introduced  with  a  knife. 

2  The  part  of  the  shaft  or  spindle  which  runs  in  the 
bearing. 

8  About  one  gallon  per  thousand  miles  appears  to  be  a 
fair  allowance  for  a  good-sized  car. 


90  MOTORS   AND   MOTORING 

kind  specially  suitable  for  use  at  high  temperatures, 
therefore  we  are  precluded  from  using  vegetable  and 
animal  oils  for  this  purpose,  as  they  partially  decom- 
pose at  high  temperatures,  liberating  fatty  acids,  and 
forming  pitch.  But  mineral  oils  stand  heat  much  bet- 
ter, and  are,  therefore,  exclusively  used  for  cylinders, 
and  also,  as  a  matter  of  fact,  for  most  engine  lubrica- 
ting purposes. 

High-class  cylinder  oils  are  very  expensive;  their 
manufacture  is  in  the  hands  of  a  very  few,  and  the 
poor  motorist,  who  must  have  the  best  if  he  is  to  be 
economical,  must  patiently  wait  for  some  relief  till  the 
Macalpine  process  is  commercially  worked  on  a  fairly 
large  scale. 

Needless  to  say,  the  many  secondary  bearings  about 
a  car  can  be  efficiently  lubricated  by  a  high-class  heavy 
machinery  oil,  but  it  is  best  to  follow  the  advice  of  the 
maker  in  these  matters.  The  preparation  and  use  of 
grease  has  been  referred  to  in  the  article  on  Chains,  and 
need  not  be  further  touched  on.  Other  matters  relat- 
ing to  lubrication  have  also  been  explained  in  various 
connections,  and  are  therefore  not  mentioned  in  this 
article,  which  could  be  profitably  much  extended  if  the 
exigencies  of  space  would  permit. 

71.  Fuel  Efficiency  of  the  Car. — We  have  seen  in 
Article  23  that  all  the  energy  of  the  fuel  we  can  expect 
to  get  in  the  form  of  work  at  the  crank-shaft  is  15 
per  cent.,  but  there  are  further  serious  losses,  due  to 
friction,  before  power  is  available  at  the  driving  wheels. 
Thus  we  must  expect  a  loss  of  about  15  per  cent,  from 
crank-shaft  to  propeller-shaft  through  the  friction  in 
the  gear-box,  and  a  further  loss  of,  say,  20  per  cent, 
from  propeller  to  cross-shaft  after  the  bevel  wheels 
have  worn  a  bit,  and  a  still  further  loss  of  15  per  cent, 
from  the  cross-shaft  to  the  road  wheels  through  the  more 
or  less  dirty  chains;  this  of  course  means  that  the  total 
,  85X80X85X15  rt  _._,  0  CH 
efficiency  may  be  looxlooxlooxloo  =0867,  or  8-6T 

per  cent.,  or  only  a  little  more  than  one-twelfth  of  the 


MOTORS   AND   MOTORING  91 

potential  energy  of  the  fuel  is  available  as  useful  work 
at  the  tires  of  the  driving  wheels. 

72.  On  Selecting  a  Car. — The  great  motor  car  exhi- 
bitions never  fail  to  attract  numbers  of  intending  pur- 
chasers.   Not  a  few  of  these  having  formed  ideas  as  to 
what  they  want,  they  have  decided  upon  the  sum  of 
money  they  will  lay  out,  the  form  and  general  arrange- 
ment of  the  tonneau,  and  perhaps  even  its  color,  the 
number   of  cylinders   and   approximate  power   of  the 
engine  have  been  settled,  whilst  the  kind  of  transmis- 
sion, the  ignition,  lubricating  and  cooling  systems,  and 
the  many  other  important  features  their  ideal  car  is  to 
have,  have  been  thought  out;  but,  after  a  painstaking 
tour  of  the  stands,  the  potential  motorist  will  find  the 
nearest  approach  to  his  requirements  is  a  compromise, 
as,  indeed,  every  car  is;  but  there  is  generally  on  any 
well-known  car  some  particular  feature  that  is  more 
perfect  in  its  way  than  that  on  others  in  the  market, 
and  this  is  often  why  a  certain  car  is  selected  in  prefer- 
ence to  others.     Of  course,  if  this  feature  is  a  really 
important  one,  one  that  represents   higher   efficiency, 
increased  simplicity  or  greater  durability,  then  the  selec- 
tion may  be  a  very  judicious  one,  but  if,  on  the  other 
hand,  it  is  merely  the  form,  or  even  the  color  and  finish 
of  the  body,  as  perhaps  it  more  often  is  than  some  pur- 
chasers would  willingly  admit,  the  least  said  about  the 
matter  the  better.     Not  so  very  long  ago  it  was  far 
from  an  easy  matter  to  select  a  satisfactory  American 
made  car,  but  fortunately  that  is  not  the  case  now,  as 
cars  more  perfect  in  design,  materials,  workmanship, 
construction,  finish,  and  durability  are  not  to  be  found 
anywhere  in  Europe  than  those  which  are  turned  out 
by  our  most  famous  makers.     And  this  can  be  safely 
said  whilst  bearing  in  mind  and  duly  appreciating  the 
splendid  vehicles  that  have  been  and  are  being  con- 
structed abroad,  more  particularly  those  which  owe  their 
development  to  French,  English,  and  German  genius. 

73.  Car  Driving. — The  principal  makers  of  cars  and 
motor  cycles  supply  their  customers  with  printed  par- 


92  MOTORS   AND   MOTORING 

ticulars  of  all  the  important  details  of  their  vehicles, 
and,  in  addition,  very  concise  driving  directions;  they 
also,  as  a  rule,  willingly  allow  purchasers  to  spend  a 
few  days  in  their  works  to  enable  them  to  become  ac- 
quainted with  the  internal  economy  of  the  mounts  they 
purchase.  This  is  a  privilege  that  everyone  should 
avail  himself  of,  even  if  he  employs  a  professional 
driver,  as  it  is  only  by  getting  a  good  grasp  of  how 
everything  is  arranged  in  a  car,  and  of  how  the  prin- 
cipal adjustments  and  connections  are  made,  in  fact, 
by  learning  the  functions  of  every  detail  of  the  mech- 
anism of  his  car,  that  he  will  in  time  become  independ- 
ent of  a  driver's  company  or  assistance,  when  such  is 
not  desired,  and  be  able  to  detect  any  attempt  to  impose 
where  repairs  are  concerned.  A  purchaser  should 
always  arrange  with  the  maker  for  a  few  lessons  in 
driving,  and  for  one  or  two  long  runs;  he  will  then  be 
taught  the  use  of  the  various  handles,  levers,  fittings, 
and  accessories  used  by  the  driver  in  running  the  car, 
and  will  be  shown  how  the  speed  of  the  engine  can  be 
varied  by  advancing  and  retarding  the  spark,  also  by 
varying  and  throttling  the  mixture,  and  by  a  combina- 
tion of  these.  The  ignition  system  will  be  explained, 
and  he  will  be  shown  how  the  accumulators  are  tested 
and  the  current  switched  on  and  off.  The  lubricating 
system  will  be  carefully  traced  out,  and  he  will  learn 
what  to  do,  so  that  in  starting  the  car  everything  that 
requires  it  will  be  properly  lubricated,  whilst  the  use 
of  the  clutch  and  accelerator  will  be  made  clear,  and 
the  action  of  the  cooling  system  gone  into.  After  the 
owner  has  been  through  all  this,  he  will  be  taken  out 
for  a  trial  spin  on  some  quiet  road,  or  perhaps  in  one  of 
the  parks  early  some  morning,  and  he  will  be  able  to 
get  a  little  actual  driving  practice,  at  first  with  the  car 
running  on  its  lowest  speed :  he  will  then  soon  find  that 
there  is  much  to  learn  before  he  can  with  any  confidence 
steer  the  vehicle,  manipulate  the  clutch,  and  apply  the 
brake  to  stop  the  car  with  the  skill  required  to  avoid 
sudden  strains  and  shocks.  After  he  has  shown  some 


MOTORS   AND   MOTORING  93 

proficiency  in  these  matters,  he  will  be  taught  how  to 
change  the  gear  from  a  low  one  to  a  higher,  and  from  a 
high  one  to  a  lower,  without  injuring  the  teeth  of  the 
wheels;  he  will  be  warned  against  trying  to  reverse  the 
car  by  changing  the  gear  before  it  has  been  brought 
to  a  standstill.  But  all  this  time  he  may  have  been 
merely  doing  the  fancy  work  (which  can  be  mastered 
in  a  very  short  time),  his  instructor  controlling  the 
running  of  the  engine  by  advancing  or  retarding  the 
spark  and  regulating  the  throttle,  operations  that  he 
will,  after  the  first  two  or  three  lessons,  soon  begin  to 
perform  with  a  fair  amount  of  readiness.  Only  experi- 
ence of  this  kind  will  enable  him  to  master  the  art  of 
driving  in  such  a  way  that  he  almost  instinctively  knows 
what  to  do  the  instant  any  adjustment  is  required.  It 
is  hardly  necessary  to  remark  that  the  qualities  neces- 
sary to  make  a  good  driver  are  not  possessed  by  every- 
one, but  it  is  simply  astonishing  to  find  that  so  many 
possess  an  instinctive  aptitude  for  motoring.  They  are 
soon  able,  without  any  previous  mechanical  training,  to 
skillfully  manipulate  their  car,  and  intelligently  diag- 
nose the  cause  of  stoppage,  and  if  they  have  nerve  and 
presence  of  mind,  they  are  equipped  by  nature  to  enjoy 
to  the  full  a  delightful  pastime,  for  there  is  a  peculiar 
and  indescribable  pleasure  in  feeling  that  you  have  at 
your  command  an  obedient  agent  that  will  instantly 
respond  to  your  slightest  command,  and,  should  your 
car  be  a  fairly  powerful  one,  carry  you  up  the  steepest 
hill  with  a  rush  that  must  be  experienced  to  be  appre- 
ciated; indeed,  the  only  rational  excuse  for  using  a 
powerful  car  is  to  be  able  to  negotiate  hills  at  the  legal 
limit  speed,  and  to  rapidly  accelerate  speed  after  slow- 
ing down  or  stopping;  but  this  very  power  is  one  that 
is  too  often  abused  by  unskillful  owners  and  inconsid- 
erate and  careless  drivers,  particularly  in  the  abnormal 
use  of  the  main  brakes,  which  are  worked  by  the  side 
hand  lever,  which  is  really  an  emergency  brake,  one 
that  should  only  be  used  when  it  is  necessary  to  pull  the 
car  up  very  short  to  avoid  an  accident?  and  it  can  never 


94  MOTOBS    AND    MOTOEING 

be  effectively  used  without  the  tires  in  particular  suf- 
fering. A  skillful  and  careful  driver  always  assumes, 
on  approaching  a  cross-road,  that  something  is  about  to 
move  out  of  it  that  might  come  in  his  way,  or  in  near- 
ing  a  bend  or  turn  in  the  road  that  there  is  a  flock  of 
sheep  approaching,  or  something  of  the  kind  blocking 
the  way;  he  then  slows  down  enough  to  enable  him  to 
pull  up  the  car  in  time,  by  instantly  but  gradually  ap- 
plying the  foot-brake.  It  will  be  seen  that  all  this  really 
represents  organized  common  sense;  it  means  that  a 
reliable  good  car  can  be  driven  for  years  with  little  de- 
preciation, and  the  annual  expenditure  of  a  compara- 
tively small  amount  on  repairs  and  up-keep,  if  it  is 
carefully  and  cleanly  kept  in  running  condition,  all 
bolts  and  nuts  liable  to  work  loose  being  examined,  and 
screwed  up  when  necessary  after  each  trip,  due  atten- 
tion being  paid  to  lubrication,  and  the  car  itself  driven 
with  a  sympathetic  consideration  for  its  powers  of  en- 
durance. On  the  other  hand,  it  means  that  if  the  car 
is  roughly  used,  the  teeth  of  the  gear  wheels  may  be 
stripped,  many  parts  severely  strained,  and  the  driving 
tires  practically  destroyed  in  a  very  few  minutes. 

It  should  not  be  overlooked  that  in  locomotive  prac- 
tice a  man  has  to  spend  years  in  qualifying  to  take 
charge  of  an  engine,  and  even  then  he  is  not  competent 
to  execute  repairs,  nor  is  required  to  do  so;  and  in 
almost  every  case,  unless  a  motor-car  driver  be  a  trained 
mechanical  engineer,  or  at  least  has  had  some  good 
workshop  experience,  it  is  false  economy  to  allow  him 
to  even  take  up  brasses  and  do  such  jobs ;  as  to  perform 
them  satisfactorily  no  small  amount  of  skill  is  required. 
It  would  not  be  going  too  far  to  say  that  the  least  im- 
portant part  of  the  training  of  a  driver  is  that  which 
enables  him  to  take  charge  of  the  wheel  and  skillfully 
steer  a  car  through  crowded  traffic.  The  really  profi- 
cient man  is  able  to  detect  the  slightest  thing  abnormal 
about  the  running  of  a  car,  and  locate  its  cause  before 
anything  serious  occurs.  And  if  his  training  has  been 
of  the  right  kind,  and  he  takes  a  pride  in  his  work,  he 


MOTOES    AND    MOTOKING  95 

will  keep  his  car  so  that  everything  about  it  is  in  the 
pink  of  condition,  and  screwed  up  to  concert  pitch 
when  required  for  use. 

74.  How  to  Start  a  Car. — As  some  reader  may 
become  possessed  of  a  second-hand  *  car,  and  therefore 
will  not  be  in  so  fortunate  a  position,  so  far  as  tuition 
is  concerned,  as  the  owner  of  a  new  car,  it  will  be  as 
well  to  very  briefly  explain  what  is  usually  done  in 
starting  the  engine  and  car.  But  as  much  information 
bearing  on  driving  has  been  given  in  the  articles  on 
Ignition,  Cooling,  Gear-changing,  Carburation,  and 
Carburettors,  etc.,  the  references  to  these  matters  will 
be  very  brief.  The  first  thing  that  may  be  done,  is  to 
see  that  the  tanks  are  filled  with  enough  gasolene  and 
water  for  the  purposed  run,  and  then  make  sure  that 
all  the  working  parts  are  thoroughly  lubricated,  and 
that  the  sight-feed  lubricators  are  adjusted.  Next  turn 
on  the  gasolene  to  supply  the  carburettor,  and  flood  the 
latter  by  moving  the  float-needle  up  and  down  two  or 
three  times,  fully  opening  the  mixture  throttle,  push  on 
the  electric  switch,  and  retard  the  ignition  to  prevent 
back-firing;  then  place  the  change-speed  lever  in  the 
neutral  position,  and  smartly  turn  the  starting  handle 
till  the  explosions  drive  the  engine,  being  careful  always 
to  exert  the  effort  in  pulling  the  handle  upwards,  and 
refrain  from  pushing  it  downwards,  as,  should  back- 
firing accidentally  occur  whilst  it  is  being  pushed  down, 

1No  one  who  is  not  an  experienced  mechanical  engineer 
should  be  tempted  to  buy  a  second-hand  car  without  the 
advice  of  an  expert,  as  the  art  of  the  horse  dealer  in  doctor- 
ing a  horse  is  not  to  be  compared  with  that  which  is  some- 
times practiced  in  preparing  old-fashioned,  or  even  obsolete, 
cars  for  sale.  In  many  cases,  too,  modern  cars  that  have 
been  very  badly  treated,  and  whose  mechanisms  are  prac- 
tically worn  out,  are  made  to  look  like  new  ones,  to  say 
nothing  of  the  freaks  which  are  faked.  On  the  other  hand, 
excellent  cars  can  be  picked  up  sometimes  at  less  than  half 
their  original  cost,  as  some  owners  are  never  long  satisfied 
with  their  vehicles,  and  must  have  a  new  one  at  least  once 
a  year. 


96  MOTOES   AND   MOTOKING 

it  would  be  violently  and  suddenly  forced  upwards,  with 
almost  certain  injury  to  the  arm.  The  clutch-pedal 
may  now  be  depressed,  and  the  gear-lever  pulled  over 
till  the  gear  for  the  first  speed *  is  in  mesh,  and  the 
latch  of  the  lever  slips  into  its  notch  in  the  quadrant, 
when  the  clutch  may  be  gently  let  in  to  allow  the  car 
to  gradually  accelerate  its  speed.  (Eefer  to  Article  61.) 


CONCLUDING   REMARKS 

75.  In  looking  over  the  contents  of  this  little  work, 
the  author  is  forcibly  reminded  that  many  matters 
which  could  not  fail  to  interest  the  motor  novice  have 
been  omitted  owing  to  the  want  of  space.  This  being 
so,  brief  reference  to  some  of  the  more  important  omis- 
sions may  be  made  in  this  concluding  article. 

One  of  the  qualities  of  a  car  which  does  not  generally 
receive  the  attention  it  deserves  is  ACCESSIBILITY;  it 
is  true  that  much  has  been  done  to  improve  cars  in 
this  direction  during  the  past  year  or  two,  but,  although 
it  is  quite  the  exception  to  find  engines  whose  valves 
are  not  readily  accessible,  the  same  thing  can  scarcely 
be  said  for  clutches,  which  should  always  be  arranged 
so  that  an  adjustment  is  easily  made;  and  many  other 
parts,  such  as  gear-cases,  differentials,  etc.,  should  be 
get-at-able  in  the  sense  that  they  can  be  taken  out  for 
repairs  without  dismantling  half  the  car;  and,,  more 
particularly,  in  every  case  those  parts  which  periodically 
require  adjusting,  or  occasional  attention  on  the  road, 
should  be  as  accessible  as  possible.  In  some  cars  the 
driving  and  controlling  fittings  are  not  placed  so  that 
they  can  be  worked  with  ease  by  drivers  whose  arms 
and  legs  are  of  average  length;  this  is  particularly  the 
case  with  push  pedals,  which  might  with  advantage  be 

1  Needless  to  say,  the  novice  should  wait  till  he  is  pro- 
ficient in  driving  on  the  lowest  speed  before  he  attempts  to 
run  his  car  on  a  higher  one. 


MOTOES    AND   MOTOBING  97 

made  adjustable,  as  (spinal  columns  being  fairly  con- 
stant in  length)  the  difference  between  a  tall  person  and 
a  short  one  is  mainly  one  of  legs.  RELIABILITY  is  a 
quality  the  importance  of  which  cannot  be  overrated, 
and  the  various  reliability  trials  here  and  abroad, 
arranged  so  that  absolutely  every  replenishment,  ad- 
justment, and  cleansing  of  the  cars  was  done  on  the 
road,  under  official  observation  in  the  running  time, 
have  enabled  the  judges  to  draw  up  reports  that  have 
greatly  assisted  designers  and  makers,,  and  have  led  to  a 
high  standard  of  reliabilty  being  reached.  And  the 
same  remarks  equally  apply  to  the  highly  successful 
light  car  trials  recently  made. 

The  question  of  dust-raising  by  motor  cars  has  been 
studied  and  the  results  of  the  experiments  now  being 
made  are  sure  to  be  of  great  interest  to  motorists. 
It  has  been  noticed,  in  a  general  way,  that  cars  which 
have  a  clean  nnderbody  without  any  projections,  the 
lowest  parts  at  the  back  being  higher  than  those  at  the 
front,  the  bottom  forming  a  taper  clearance,  raised 
the  least  amount  of  dust  at  a  given  speed.  It  has  also 
been  noticed  that  the  amount  of  dust  raised  increases 
with  the  size  of  the  tires,  other  things  being  the  same, 
and  that  exhausts  impinging  on  the  ground  increase 
the  evil;  but,  fortunately,  these  are  matters  that  we 
shall  know  more  about  soon,  and,  if  some  simple  means 
of  mitigating  what  is  fast  becoming  a  grave  nuisance, 
both  to  motorists  and  other  users  of  our  roads,  can  be 
devised,  it  will  be  hailed  as  a  great  boon.  Of  course, 
whatever  can  be  done  in  this  direction  will  only  partly 
solve  the  problem,  the  real  solution  of  which  is  the  mak- 
ing of  waterproof  roads.  But  if  such  roads  were  once 
made  and  used  only  by  automobiles,  there  would  be 
comparatively  little  depreciation;  as  it  is,  on  ordinary 
roads,  the  tires  lick  up  and  disperse  the  road  detritrus 
(rubbish  of  attrition),  and  in  so  doing  accelerate  the 
disintegration  of  the  surface;  but,  of  course,  the  injury 
done  in  this  way  is  slight  compared  with  the  hammer- 
ing effect  of  horses'  feet  on  the  metaling,  which  sooner 


98  MOTOES   AND   MOTOKING 

or  later  destroys  the  surface,  whatever  it  may  be  made 
of.  It  is  not  easy  to  foresee  how  this  road  problem  is 
to  be  ultimately  solved,  but  if  motorists  continue  to 
increase  in  number  at  the  present  rate,  they  will  ere 
long  be  strong  enough  to  influence  for  the  common 
good  those  bodies  who  are  responsible  for  the  up-keep 
of  our  roads. 

STEAM  CARS  have  been  greatly  improved  during  the 
past  two  or  three  years,  and  when  their  principal  points 
are  compared  with  those  of  gasolene  cars,  it  is  not  easy 
to  understand  why  the  former  should  be  so  much  neg- 
lected by  the  motorist.1  It  is  true  they  did  not  at  one 
time  compare  very  favorably  with  the  gasolene  car; 
boiler2  troubles  were  frequently  heard  of,  particularly 
in  cases  where  boilers  which  required  skillful  handling 
were  in  the  hands  of  careless  and  inexperienced  drivers. 
Then,  again,  fuel-consumption  was  usually  excessive,  to 
say  nothing  about  the  difficulty  of  getting  a  supply  of 
suitable  water  two  or  three  times  on  a  long  run.  But 
all  that  is  a  matter  of  the  past,  and  the  modern  steam 
car  of  the  best  make  can  be  driven  a  distance  of  over 
a  hundred  miles  without  a  stop  for  water  or  fuel,  and 
with  no  more  attention  than  is  required  by  the  most  per- 
fect gasolene  car,  whilst  by  using  the  throttle  the  range 
of  engine  power  is  so  great  that  no  change-speed  gear  is 
required,  and  the  condensation  of  steam  is  so  complete 
that  the  exhaust  is  rarely  seen.  In  addition  to  these 
good  features,  the  steamer  is  a  splendid  hill  climber, 
and  its  smooth  vibrationless  running  on  a  decent  road 
is  what  many  acclaim  to  be  the  poetry  of  motion. 
Indeed,  if,  in  selecting  a  car,  absence  of  vibration,  for 
some  reason  or  another,  is  considered  the  most  impor- 
tant factor,  then  it  would  be  a  safe  plan  to  paraphrase 
the  famous  whist  injunction — "When  in  doubt,  select 
a  steamer,"  and  a  selection  could  safely  be  made  from 

1  Refer  to  Article  2,  where  it  will  be  seen  that  the 
variety  of  steam  cars  is  small  compared  with  gasolene  ones. 

a  Makers  prefer  to  call  these  steam  generators,  or,  briefly, 
generators. 


MOTOES   AND   MOTORING  99 

the  foreign  Miesse,  or  Serpollet,1  or  the  American 
White,  to  mention  only  three  of  the  best  known. 
Doubtless,  ere  long,  more  attention  will  be  paid  to  the 
relative  merits  of  the  two  systems,  but,  for  the  nonce, 
everyone  knows  that,  rightly  or  wrongly,  the  gasolene  car 
is  an  easy  first  favorite,  and  the  fundamental  fact  that  it 
is  more  economical  to  burn  the  fuel  in  the  cylinder  of  the 
engine  than  in  a  boiler  will  always  be  in  its  favor,  not- 
withstanding its  drawbacks  and  the  possibilities  of 
trouble  in  connection  with  carburettors  and  ignition 
systems. 

Should  the  day-dreams  of  some  of  our  advanced 
thinkers  ever  eventuate  in  the  creation  of  a  gasolene  tur- 
bine of  great  range  of  power  and  moderate  weight,  it 
is  safe  to  say  that  a  new  era  in  automobilism  would 
rapidly  dawn.  But  even  taking  things  as  they  are,  it 
is  possible  for  any  man  who  can  afford  to  keep  a  dog- 
cart, to  run  a  light  car  and  bring  a  new  joy  into  his 
life,  with  little  or  no  additional  expense,  if  he  is 
mechanically  inclined,  and  is  not  afraid  of  attending 
to  the  car  himself. 

1Mons.  Serpollet  has  perhaps  done  more  than  any  man 
living  to  develop  the  possibilities  of  the  steam  car.  Indeed, 
it  can  be  safely  said  that  what  he  does  not  know  about 
flash  boilers  it  is  not  worth  knowing. 


INDEX 


Accelerator,  56 
Accessibility,  96 
Accumulators,  38 

Charging,    45 

Charging      from      Electric 
Batteries,    45 

Charging      from      Electric 
Mains,   46 

Efficiency  of,   48 

Internal   Resistance   of,    48 

Rate  of  Charging  and  Dis- 
charging,   47 

Spare,  48 
Adjustments,    96 
Air,  Auxiliary,  21 
Air,   Composition  of,  31,' 
Air-Cooled   Cylinders,   58 
Air  Fans,  61 
Air  Locking,   61 
Air     required     for     Carbura- 

tion,  32 

Alcohol,    Denaturized,    30 
Ammeter,   The,  47 
Ampere,   The,   40 
Automobile    Club    of    America, 

.     Reference  to,  77 
Auxiliary  Air,  21 


Back-Firing  or  popping,  53,  63 

Balanced  Engines,   83 

Balancing  Single  Cylinder  En- 
gine,  84 

Two  Cylinder  Engine,   84 
Three  Cylinder  Engine,    84 
Engines  with  four  or  more 
Cylinders,   85 

Ball   Bearings,    78 

How   to   adjust  them,    79 
Renewing  them,    79 

Batteries,   38 
Primary,   39 
Secondary    or    Storage,    38 

Bearings,   Ball  v.  Plain,   78 
Lubrication  of,   79 

Beau     de      Rochas,     or     Otto 
Cycle,    8 

Benzine,  30 

Benzol,   30 

Blake,    Mr.    F.    C.,    Reference 
to,  42 

Bollee  Car,  Reference  to,  55 


Brakes,  76,  77 

Emergency    or    Auxiliary, 

76,  77 

Burning  Point  of  Gasolene,  29 
By-Pass  for  Muffler,   63 


Canstatt  Daimler  Car,   Refer- 
ence to,   73 
Carburation,  16    . 
Carburettor,    Hot    Jacket    for, 

18 

Kreb's,   Reference  to,   23 
Longuemarre,       Reference 

to,  20 

Stoppage  in  Nozzle,   21 
The  De  Dion  Surface,  24 
The   Float-Feed  or  Spray, 

The  Surface,  24 
Carburettors,          Fundamental 
Condition    for    Perfect 
working,    23 

Cardan  Shaft  and  Joints,  67 
Chain  Driving,   75 
Chains,    Cleaning    and    Lubri- 
cating them,   76 
Varying   Tightness   of,    80 
Charge   Volume   Throttling,    55 
Chassis,   Definition   of,   2 
Clearance  Space,   10 
Clutch,  The,  69 
Fierce,   70 

Fitting    the    Leather,    70 
How  to  Adjust,   70 
Leather  Dressing,  71 
Letting  it  in,  77 
Loss  of  Power  due  to  Slip, 

70 
Nursing    of    In    Mounting 

Hills,    56 
Collan  Oil,  71 

Combining  Proportions  of  C 
and  O,  and  H  and  O, 
31 

Proportions    of    Illuminat- 
ing Gas  and  Air,   17 
Combustion,   Air  required  for, 

31 
Commutator,   42 

Panhard  Type,  54 
Contact  Breaker,  42 


101 


102 


INDEX 


Controlling  by   Throttling   the 

Mixture,    55 
Cooling  Efficiency,   upon  what 

it    depends,    58 

Crossley  Car,  Reference  to,  88 
Crossley,     Messrs.,     Reference 

to,  88 

Cylinder  Cooling,   Forced   Cir- 
culation   System,    66 
Cooling,       Thermo-Syphon 

System,   60 

Cooling     System,     Rubber 
Hose    Connections,    60 
Wall,   Temperature  of,  58 

Davy  Lamp,  30 

Dead  Centre  of  Crank,  7 

Decauville   Car,    Reference   to, 
87 

De   Dion   Car   Surface   Carbu- 
rettor, 24 
Sparking  Plug,  43 

Differential      Explanation      of 

Principle   of   Gear,    69 
Shaft,  75 

Distance  Rod,  75 

Dressing    for    Clutch    Leather, 

Drivers'     Training,     etc.,     Re- 
ferred to,   94 

Duryea   Car,   Reference  to,   55 
Dust  Raising  Nuisance,   97 

Earth  Wire,  44 

Efficiency,  Fuel  of  the  Engine, 

Mechanical,   of  Engine,    33 
Electric  Ignition,   35,   37 
Electro-Magnetic   Ignition   Re- 
ferred  to,    37 
Electro-Motive   Force,    40 
Engines,     Balancing,    Various, 

84 

Balancing,     Primary     and 

Secondary   Couples,    85 

Unbalanced  Inertia  Forces, 

'84 
Epicyclic  Gear,   Reference   to, 

Excellence   of  American  Cars, 
91 

Exhaust    Gases,    Objectionable 

Odour,   30 

In   relation   to   Dust  Rais- 
ing, 97 

External  Plug  Gap,  43 

Foot-brake,  73,  76,  77 
Fuel  Efficiency  of  a  Car,  90 

Efficiency  of  Engines,  34 

The,  28 

Other  than  Gasolene,  30 
Fuller's  Earth,   70 


Gasolene,  28 

Its  disadvantages,   etc.,   29 
Straining  and  Filtering,  28 

Gear- Box,   65 

Gear  Changing,   73 

Gillet-Foust    Motor,    Reference 
to,   57 

Governing   and   Controlling,    49 
On  the  Exhaust,  50 
On   the   Inlet,    49 
On  the  Throttle,   49 

Governor,    Centrifugal,    Refer- 
ence to,  55 

Grease   Box,    Stauffer,    89 

Grinding  in  Valves,  15 

High-Tension   Ignition,    37 
Hooke,  Dr.,  Reference  to,  67 
Horse-power,   32 

Brake,   33 

Indicated,  33,  51 
How  to  Start  a  Car,  95 


Ignition,   35 

Advancing  and  Retarding, 
50 

Late,  52 

Pre-,  52 

Tube,    35 
Indicators,  51 
Induction  Coil,   41 
Internal    Combustion    Engine, 

Interrupter,  44 


James  and  Browne  Car,  Ref- 
erence to,  88 

Kreb's  Carburettor,  Reference 
to,  23 

Lampblack  for  coating  Con- 
ducting Surfaces,  61 

Lanchester  Car,  Reference  to, 
85,  88 

Late  Ignition,  52 

Leaky  Valves,  14 

Lenoir    Engine,    Reference    to, 

Letting  in  the  Clutch,   76 
Live-Axle  or  Cardan  Drive,  67 
Longuemarre  Carburettor, 

Reference   to,    20 
Lubricating  Chains,   76 

Ball   Bearings,    79 

Springs,    89 
Lubrication,    85 

Automatic    Positive    Feed, 
88 

Forced,   89 

Oils,  89 


INDEX 


103 


Lubrication,  Replenishing 

Crank-Chamber,    87 
Sight-feed,    87 
Vitiated  Oil,   87 
Water-heated  Sights,   88 

Manograph,      Hospitalier-Car- 

pentier,    51 

Maudslay   Car,  Reference   to,  86 
Mechanical    Efficiency    of    En- 
gine,   33 
Mercedes    Car,    Reference    to, 

73,    86 

Miesse  Car,  Reference  to,  98 
Mixture,   Richness  of,   20 
Mors  Car,  Reference  to,  54 
Motor    Car,    Elements    of,    80 

Definition  of,  xi 
Mufflers,    Principle   of,    62 

By-Pass,    63 

Typical  Examples,  62 

Nobel,  Reference  to,  31 

Odour  of  Exhaust  Gases,  xi 
Ohm,   The,   40 
Oil,   Collan,    71 

For    Cylinder    Lubrication, 

Otto  Cycle,   7 

Panhard  Clutch,  71 
Petroleum,     Fractional    Distil- 
lation  of   Crude,    28 

Spirit,  28 

Plug-Gap,    External,    43 
Popping  or  Back-Firing,  63 
Pre-Ignition,   52 
Primary    Batteries,    39 
Pump,   Centrifugal,   59 

Gear,  59 

Rotary  force,   59 

Radiators,       Multitubular       v. 

Coil,   60 
Best   kind   of   Surface  for, 

Refining   Tallow,    76 

Reliability,    97 
Trials,    97 

Roads,   Waterproof,   97 

Road  Wheels,   83 

Alignment    of,    83 
Artillery  v.  Wire,   83 
Factors        which        decide 
size,  84 

Scavenging,   12 

Second-hand      Cars,      Precau- 
tions  in   Buying,    95 
Selecting  a  Car,  91 
Serpollet  Car,  Reference  to,  98 


Skidding,  78,  81 

Spare   Accumulators,    48 

Sparking  Plug,  43 

Specific  Gravity,  34 

Springs,      Special,      for     Solid 

Tires,    80 
Lubricating,    89 
Sprocket  Wheels,  75 
Starting  Handle.     How  to  use 

it,   95 

Stauffer   Grease   Boxes,    89 
Steam  Cars    v.  Gasolene  Cars, 

Steering  Gear,  83 
Stretcher  Bar,  75 
Switch,  The,  44 

Tallow  Refining,   76 
Temperature^   g  of        Cylinder 

Testing  on  a  Closed  Circuit,  48 
Thermo -Syphon      System      of 

Cylinder    Cooling,    60 
Throttling  the  Mixture,   55,   76 
Tube  Ignition,  35 
Tires,      Abnormal      wear      of, 

Front   ones,    83 
Effect      of      Light,      Dirt, 
Rust,    and    Grease,    81 
Fixing  Solid  ones,   80 
Inflating,   82 
Inner   Tubes,    82 
Size    in    Relation    to    Dust 

Raising,   97 
Skidding,    78,    81 
Soft,  82 

Solid  v.   Pneumatic,    80 
Treatment  of  Burst  Ones, 

Treatment   of,    when   Laid 
up,  82,  83 

Universal    Joints    (Hooke's    or 
Cardan's),    67,    81 

Valves,    Automatic   Inlet,    11 

Grinding  in,    15 

Leaky,  14 

Lifter,  16 

Mechanically  Operated  In- 
let, 12 

Volt,  The,  40 

Voltage  of  the  Current,  47 
Voltmeter,  The,  47 

Water-cooled   Cylinders,   59 
Water-logged   Float,    21 
Watt,  The,  41 
Wheels,   Road,  83 
White  Car,   Reference  to,  98 
Wilson-Pilcher  Car,  Reference 
to,   86 


TL 

45 


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